NAMBE 2023 Session QME-SaP: Workshop on Quantum Materials Epitaxy Poster Session

We are in the midst of the second quantum revolution.Research institutes and companies worldwide are working toward harnessing the power of quantum physics for technological applications. Gapless surface states on topological insulators are protected from elastic scattering on nonmagnetic impurities,¹ which makes them promising candidates for low-power electronic applications.In previous years, most research efforts on demonstrating topologically protected edge states were focused on rather exotic topological materials.^1,2However it was extremely difficult to generate strong enough edge currents out of these materials, to be practically useful for widespread applications, due to low emission currents.Hence, we are exploring more commonly used infrared materials such as InAsSb/InGaSb quantum wells (QWs) and superlattices (SLs). Both structures can be designed to have an inverted gap by elevating the hole state above the electron state, and a large emission current, in particular in the SL by enhancing wavefunction overlaps.These are critical components on establishing topological states to create the conducting edge and the insulating bulk state.This unique circumstance can create dissipationless transportof electrons in heterostructures, which is particularly important for a variety of sensing applications.Therefore, as an initial test, we examine two hybridized topological structures; one for 6.22 Å atomic lattice constant 82 Å InAs/34 Å In_0.4Ga_0.6Sb/82 Å InAs symmetric QWs on In_0.32Ga_0.68Sb substrate³ and the other for 6.10 Å atomic lattice constant 70 Å InAs_0.9Sb_0.1/35 Å GaSb SLs on GaSb substrate.Both structures are tailored for the same hybridization gap of ~60 meV.By using a combination of theoretical modeling, high-resolution x-ray diffraction, and high-resolution transmission electron microscopy, we optimize the absorber designs and their molecular beam epitaxy process to achieve high-quality materials.Growth parameters in each design are carefully coordinated to mitigate the crystalline defects to produce high-quality materials.Quasiparticle interference mapping through a scanning tunneling microscope is used to investigate the band structure of a SL sample.

[1] M. Z. Hasan and C. L. Kane, “Topological insulators”, Rev. Mod. Phys. 82, 3045 (2010).

[2] J. E. Moore, “The birth of topological insulators”, Nature464, 194 (2010).

[3] Krishtopenko and Teppe, “Quantum spin Hall insulator with a large bandgap, Dirac fermions, and bilayer graphene analog”, Sci. Adv. 4, 7529 (2018).

The alkaline earth stannates are touted for their wide band gaps and the highest room-temperature electron mobilities among all the perovskite oxides. CaSnO₃ has the highest measured band gap in this family and is thus a particularly promising ultra-wide band gap semiconductor. However, discouraging results from previous theoretical studies and failed doping attempts had written off this material as “undopable”. Here we redeem CaSnO₃ using hybrid molecular beam epitaxy (hMBE), which provides an adsorption-controlled growth for the phase-pure, epitaxial and stoichiometric CaSnO₃ films. By introducing lanthanum (La) as an n-type dopant, we demonstrate the robust and predictable doping of CaSnO₃ with free electron concentrations, n, from 3.3 × 10¹⁹ cm^-3 to 1.6 × 10²⁰ cm^-3. The films exhibit a maximum room-temperature mobility of 42 cm² V^-1s^-1 at n = 3.3 × 10¹⁹ cm^-3. Despite having a smaller radius than the host ion, La expands the lattice parameter. Using density functional calculations, this effect is attributed to the energy gain by lowering the conduction band upon volume expansion. Finally, we exploit the robust doping by fabricating the CaSnO₃ -based field-effect transistors. The transistors show promise for CaSnO₃’s high-voltage capabilities by exhibiting low off-state leakage below 20 pA/μm at a drain-source voltage of 100 V and on-off ratios exceeding 10⁶. This work opens the door to future studies on the semiconducting properties of CaSnO₃ and the many devices that could benefit from CaSnO₃’s exceptionally wide band gap.

The investigation of the electrical and magnetic properties of SrRuO₃ and its associated Sr_n+1Ru_nO_3n+1 Ruddlesden-Popper phases requires a high degree of control over the isolation of the desired phase and its defect density. The growth of ruthenates is fundamentally challenging because ruthenium (Ru) resists scalable evaporation and oxidation. This bottleneck complicates the growth of SrRuO₃ films with low defect densities using inherently low-energy, ultra-high vacuum deposition techniques such as molecular beam epitaxy (MBE). Special modifications to conventional MBE such as electron-beam assisted evaporation and ozone-assisted oxidation of Ru have, so far, enabled the best defect control or the highest residual resistivity ratios (RRR = ρ_300K/ρ_2K) in SrRuO₃ films among all physical vapor deposition techniques. However, these modifications are expensive and require additional interlocks to ensure safe operating conditions.

We outline a novel technique called solid source metal-organic MBE to supply a solid metal-organic precursor with pre-oxidized ruthenium with an effusion cell atT < 200 °C, a drastic decrease from the ~ 2000 °C required to produce comparable fluxes with elemental Ru. With this technique, we demonstrate the growth of phase pure, epitaxial, and stoichiometric SrRuO₃ films with robust ferromagnetism below 150 K on SrTiO₃ (001) substrates. We simplify the route to an adsorption-controlled growth window in SrRuO₃ films, growth conditions where the films can self-regulate their stoichiometry, which is a key ingredient for successful defect control in electron-beam and ozone-assisted MBE-grown SrRuO₃ films. We discuss the intricate relationship between cation stoichiometry, magnetic domains, and RRR in epitaxial SrRuO₃ films and outline new pathways for achieving low defect densities in SrRuO₃. Using these guidelines to optimize stoichiometry and film thickness within a growth window, we achieve a RRR = 87 for a 50 nm-thick SrRuO₃ film, the highest for any SrRuO₃ film on SrTiO₃ (001) substrates. We will also illustrate how solid source metal-organic MBE is a simple and cost-effective method to enhance the capabilities of conventional MBE for the defect-controlled growth of ruthenates.

Ultra-high purity elemental sources have long been considered a prerequisite for obtaining low impurity concentration in compound semiconductors in the world of molecular beam epitaxy (MBE). Furthermore, to realize intrinsic properties, the material needs to be nearly free of intrinsic and extrinsic defects. For this reason, the use of ultra-high-purity elemental sources has been the historical practice in MBE, perhaps, for the fear that impurity elements might get incorporated into the film, making it “dirty”.

In this work, we challenge this conventional MBE wisdom by presenting an extension of the hybrid-MBE approach, known as solid-source metal-organic MBE, for growing superconducting Sr₂RuO₄ films using a solid organometallic precursor, ruthenium acetylacetonate, as a source of Ru. We grew 100 nm thick (001) Sr₂RuO₄ films on (001) LSAT substrate at 900°C substrate temperature using co-deposition of Sr, ruthenium acetylacetonate, and oxygen plasma. These films are phase-pure, single-crystalline, fully coherent, and superconducting. The superconducting transition temperature of the film is 0.85 K. In contrast to the conventional MBE, which employs ultra-pure Ru metal evaporated at ~ 2000°C as a Ru source, along with reactive ozone to obtain Ru → Ru⁴⁺ oxidation, the use of ruthenium acetylacetonate precursor requires significantly lower temperature for Ru sublimation (less than 200°C) and eliminates the need for ozone.

This is the first-time realization of superconducting Sr₂RuO₄ films using ozone-free MBE. By combining our results with the recent developments in hybrid-MBE, we argue that leveraging precursor chemistry will be necessary to realize next-generation breakthroughs in the synthesis of atomically precise quantum materials. Our results establish hybrid-MBE as a viable method for growing highest quality crystals and put this technique at the forefront of vacuum deposition technologies despite the use of a “dirty” chemical precursor.

Free-standing membranes have broad applications in the creation of symmetry-mismatched, non-equilibrium, and artificial heterostructures. We use sacrificial layer method to synthesize phase-pure epitaxial SrTiO₃ membranes. In this study, we will discuss the growth of strain-engineered SrTiO₃ films using different sacrificial layer(s) grown by hybrid MBE. We characterize the as-grown films using x-ray diffraction (XRD) and atomic force microscopy (AFM). We show exfoliation and transfer of films onto dissimilar substrates, followed by their structural characterization. Finally, we use impedance spectroscopy to characterize the dielectric properties and show a bulk-like dielectric constant of ≈ 300 for SrTiO₃ membranes transferred on Au coated Si substrate.

Since the discovery of high-T_c cuprates,^[1] a plethora of research has been conducted to understand their superconducting origin. They usually have layered perovskite structures and CuO₂ planes are considered as crucial ingredients to host Cooper pairs and d-wave superconductivity. The CuO₆ coordination octahedron is elongated along the c-axis, the 3d_x2-y2 orbital dominantly contributes to the electronic structure at the Fermi level.^[2] In 2019, a totally different type of cuprate superconductor was discovered: Ba₂CuO_4−δ (bulk T_c ~ 73 K for δ = 0.8)_.^[3]The octahedron of Ba₂CuO_4−δ was compressed along the c-axis, hence it becomes a multi-band system composed of 3d_x2-y2 and 3d_3z2-r2 orbitals. Moreover, oxygen vacancies even exist on the CuO₂ plane. These unique characteristics of Ba₂CuO_4−δ strongly sugges tthat the Cooper pair behavior is different from previously reported cuprate superconductors. Hence the study of Ba₂CuO_4−δ is expected to contribute to unveiling clues about the superconducting mechanism of high-T_c cuprates.

Unfortunately, the synthesis of Ba₂CuO_4−δ poses significant challenges. Ba-Cu-O compounds energetically prefer forming the Ba₂CuO₃ phase (a 1D CuO chain structure), hence strong oxidation is required to achieve the desired Ba₂CuO_3.2 phase. Li et al.achieved superconducting Ba₂CuO_4−δ specimens by high-pressure synthesis methods.^[3] But the chemical instability and polycrystalline structure limited deeper understanding of its electronic structure and superconductivity. Epitaxial thin film growth can be an alternative approach since it provides a strong oxidation environment with a large surface-to-volume ratio, a low reaction temperature, a pseudomorphic constraint from the substrate, and the ability to reveal the electronic structure with angle-resolved photoemission spectroscopy. In this study, using oxide MBE, we grew epitaxial thin films of the precursor phase of the Ba₂CuO_4−δ superconductor, Ba₂CuO₃,and its homolog, Sr₂CuO₃. After growth, the Ba₂CuO₃ and Sr₂CuO₃ films were oxidized by various methods such as post-growth ozone exposing or topotactic oxidation. We characterized the cuprate films by reflection high-energy electron diffraction (RHEED), x-ray diffraction (XRD), and atomic force microscopy (AFM). Our work on a thin-film approach toward single-crystalline A₂CuO_4−δ(A: Ba, Sr) superconductors will be presented.

References

[1] J. G. Bednorz et al., Z. Phys. B Condens Matter64,189 (1986).

[2] H. A. Jahn et al.,Proc. R. Soc. London, Ser. A161, 220 (1937).

[3] W. M. Li et al., Proc. Natl. Acad. Sci. U.S.A. 116, 12156 (2019).

Rare earth-based Heuslers are prospective materials platforms for magnonics, topological spin texture, superconductivity, THz spintronics, etc. [1, 2]. The magneto-mechanical coupling in these materials allows for better control and manipulation of the primary order parameter and magnetic flexibility [3]. Here, we demonstrate novel flexomagnetic responses i.e., the coupling between strain gradient and magnetism, and strain-induced superconductivity, in GdAuGe Heusler membranes. The thin films of GdAuGe Heusler composition have been grown on monolayer Graphene/ Ge (111) by molecular beam epitaxy (MBE). GdAuGe films are then mechanically exfoliated to form free-standing rippled membranes.

GdAuGe shows an antiferromagnetic ordering below ~17 K, which is sustained when a homogeneous strain is applied. However, the application of strain gradient dramatically alters the magnetic ground state of GdAuGe in the rippled membranes. A phase diagram of the rippled GdAuGe membranes is shown in Fig. 1(a). Notably, a moderate strain gradient of a few tenths of a percentage transforms the ground state from antiferromagnetic to unconventional ferrimagnetic phases. These ferrimagnetic ground states in the rippled membranes offer the possibility of discovering spin reorientation and other unique magnetic phenomena; the most exciting observation is the emergence of superconductivity in GdAuGe membranes when a very large strain gradient is applied, with superconducting transitions occurring at low temperatures below ~3.5 K. Figure 1(b) shows the magnetic characterization of a superconducting GdAuGe rippled membrane.

At present, the microscopic origin of flexomagnetism and its effects on the thermodynamics of spin reorientation and phase transitions in these membranes remain unclear. Advanced spectroscopic measurements and magneto-transport experiments, combined with theoretical modeling, are planned to further investigate the phenomena in these rippled membranes.

References

1. Graf, Tanja, et al. "Simple rules for the understanding of Heusler compounds." Progress in solid state chemistry 39.1 (2011): 1-50.

2. Kawasaki, Jason K. "Heusler interfaces—Opportunities beyond spintronics?." APL Materials 7.8 (2019): 080907

3. Du, Dongxue, et al. "Epitaxy, exfoliation, and strain-induced magnetism in rippled Heusler membranes." Nature Communications 12.1 (2021): 1-7

The platinum group metals like Ir and Ru have captured significant interest in the condensed matter physics and materials science community due to the exotic electronic and magnetic properties that they exhibit when combined with oxygen. The oxides of these metals provide a unique platform to study and leverage the delicate interplay between electron correlations, crystal field and spin-orbit coupling energies. High quality thin films of complex platinum group metal oxides are hence, critical to realizing new phenomena such as the predicted unconventional superconductivity in Sr₂IrO₄. However, the platinum group metals have extremely low vapor pressures and low oxidation potentials. These factors make it challenging to synthesize their oxide thin films using an ultra-high vacuum (UHV) technique like Molecular Beam Epitaxy (MBE). Here, we have addressed these challenges using a novel solid-source metal-organic MBE approach [1,2]. We demonstrate atomically precise synthesis of binary IrO₂ using Ir(acac)₃ as the metal-organic Ir source at substrate temperatures as low as 250 ^oC. The use of the metal-organic precursor allows Ir supply at source temperatures less than 200 ^oC and enables easy oxidation due to the +3 Ir oxidation state in the precursor. Further, by combining epitaxially strained IrO₂ thin film growth on different substrates, x-ray diffraction, electron microscopy, spectroscopy techniques, and DFT calculations, we demonstrate a vital role of epitaxial strain in Ir oxidation. Thus, epitaxial strain can be an additional tuning knob to engineer metal oxidation which can aid the conventional thermodynamic and kinetic driving forces [3].

However, the true test of metal oxidation in UHV occurs at high growth temperatures where oxidation becomes increasingly thermodynamically unfavorable. Hence, in order to examine the efficacy of the solid-source metal-organic MBE approach and to realize the elusive unconventional superconducting state, we study the synthesis of Sr₂IrO₄ thin films, which is favored at growth temperatures greater than 600-700 ^oC. We will present a detailed growth study, structural characterization, electrical and magneto-transport in epitaxial Sr₂IrO₄ films, along with alternative ways to tackle the Ir oxidation challenge in UHV synthesis.

References:

[1] W. Nunn et al., "Solid source metal-organic molecular beam epitaxy of epitaxial RuO₂", APL Mater. 9, 091112 (2021)

[2] W. Nunn et al., "Novel synthesis approach for “stubborn” metals and metal oxides", Proc. Natl. Acad. Sciences 118, e2105713118 (2021)

[3] S. Nair et al., "Engineering Metal Oxidation using Epitaxial Strain", Nat. Nanotechnol. (accepted) (2023)

α-Sn, the diamond structure allotrope of Sn, is a zero-gap semiconductor with band inversion. Calculations suggest that epitaxial tensile strain induces a transformation to a topological insulator (TI) phase, while epitaxial compressive strain induces a transformation to a Dirac semimetal (DSM) phase [1,2]. When this DSM phase is confined, it is suggested to form a quasi-3D TI phase [3]. There is little consensus, however, on exactly how or if these transitions occur. The α-Sn based system is expected to have less alloy disorder and anti-site defects compared to the typical (Bi,Sb)₂(Se,Te)₃ TI system. Bulk α-Sn is also only stable at low temperatures, transforming into the topologically trivial β-Sn above 13.2 ºC. This transformation temperature is raised above 100 ºC by epitaxial stabilization of α-Sn(a=6.489 Å) on a closely lattice matched substrate like InSb (a=6.479 Å) [4]. Even at the low growth temperatures (<30 ºC) necessary due to the phase transformation, incorporation of indium from the substrate as a p-type dopant in the epi-layer is difficult to prevent [5].

We first explore the essential role that surface preparation of the InSb(001) substrate has on both the quality and dopant density of the α-Sn films. Through magnetotransport and ultraviolet photoelectron spectroscopy measurements, we find that growth on the Sb-terminated c(4x4) surface reconstruction results in higher mobility films with significantly reduced p-type doping. Using spin- and angle-resolved photoemission spectroscopy (ARPES), we study compressively strained α-Sn films on InSb(001) at a range of film thicknesses. These measurements provide essential clarification to the band structure of α-Sn: we observe the presence of a 3D TI-like phase in 13 bilayer films. Potential causes of this contradiction to the literature will be discussed.

With the previous behavior benchmarked, we then alloy the α-Sn films with Ge to tune from low (-0.15%) compressive strain on InSb to multiple tensile strains (+0.5%, +0.8%, +1.3%) at the same film thicknesses. Morphology changes as a function of Ge alloying were studied with in-situ scanning tunneling microscopy, and strain was confirmed through XRD. Finally, the presence of topological phase transitions induced by tensile strain is studied via ARPES. Our results pave the way for a better understanding of the effect of strain and confinement on α-Sn’s band structure.

[1] Phys Rev B 97, 195139 (2018).

[2] Phys Rev B 90, 125312 (2014).

[3] Phys Rev Lett 111, 216401 (2013).

[4] J Cryst Growth 54, 507 (1981).

Ultra-wide-bandgap (UWBG) semiconducting oxides are becoming more crucial in sustainable technologies due to their promising use in applications including transparent electronics and power switching. Among them, alkaline earth stannates such as SrSnO₃ with the perovskite crystal structure have gained much interest in recent years. However, the room-temperature mobility of SrSnO₃ thin films has been shown to be limited by defective surface scattering. By using a 4 nm undoped SrSnO₃ capping layer on 19 nm La-doped SrSnO₃ thin film, the measured room-temperature mobility has been shown to improve. In this structure, charge spill over from the doped layer to the undoped layer is expected to happen as Fermi levels equilibrate. Here, we demonstrate a reversible and electrostatic doping of SrSnO₃ films grown by Hybrid molecular beam epitaxy with tunable carrier densities using electric-double-layer transistor configurations with ion gels. Using modeling and a discrete two-channel model, we show that the modulation due to gating is confined within 4 nm at the top capping layer and the modulation leads to an increase of mobility in SrSnO₃ up to 130 cm²V^-1s^-1 at 250 K. A detailed growth study combined with temperature-dependent Hall effect measurements and transport analysis will be presented.

The square-net family of materials constitute a set of crystal structures which host a wide array of quantum phenomena including charge-density wave order, magnetism, superconductivity and topological band structures. The rare-earth ditellurides (RTe₂) (Space group P4/nmm) are an especially exciting subclass of these materials whose structure consists of square-planar, conducting Te sheets interspersed with insulating R-Te corrugated layers. Due to their unique crystal structures and chemical tunability, the RTe₂ compounds offer opportunities to study the effects of topological phenomena in the context of broken-symmetry ground states. This research seeks to use molecular beam epitaxy to open new avenues for control of the low-temperature properties of these materials.

In this presentation, we describe our recent work on epitaxial growth of rare-earth telluride thin films LaTe₂ and DyTe₂ grown on MgO substrates. The good lattice match of DyTe₂ (+~1.7%) has enabled the growth of epitaxially strained films in the ultra-thin limit (<3 unit cells (uc)). Observation of RHEED oscillations along with measured surface roughness on the order of ~1uc indicates layer-by-layer growth. Out-of-plane X-ray diffraction shows intense peaks with prominent Laue fringes and rocking curve full width at half maximum of ~0.02^o. Thin films of LaTe₂ have also been produced with comparably high structural quality yet are relaxed within 1uc due to the +7% mismatch with MgO.

Using grazing incidence X-ray diffraction, a modulated superlattice in the (hk0) plane has been observed in DyTe₂ and shows a √5x√5 modulation expected for Te-deficient DyTe₂. Additionally, incommensurate modulations that cannot be indexed according to previously reported modulated structures have also been observed. The role of Te deficiency in producing these modulated structures and in relaxing epitaxial strain will be discussed.

Magnetotransport studies on LaTe₂ have revealed previously unobserved, non-saturated, negative magnetoresistance that persists to room temperature. The temperature dependence of resistivity also shows a strong dependence on growth temperature and charge density, likely resulting from variations in Te deficiency. We will discuss our current understanding of these phenomena informed by the unique features in the band structure as well as the complex defect chemistry found in these materials.

The three-dimensional Dirac semimetal Cd₃As₂ has been shown to exhibit a variety of novel physics, providing a promising platform for their study. Thin film synthesis is enabling for scientific study as well as the realization of new devices, and growth has already been carried out on GaAs, GaSb, CdTe, SrTiO₃ and mica substrates. Due to its low energy (112) surface, however, the majority of thin film synthesis routes result in this orientation, while single crystals are limited by this cleave plane when performing studies requiring pristine surfaces. By expanding compatible substrate orientations, and ultimately the Cd₃As₂ orientation, much more of the band structure may be probed via photoemission, and a broader range of device structures may be integrated with it.

Here, we present the design of II-VI buffer layers to template high quality Cd₃As₂ in the (001) and (110) orientations on GaAs substrates. Lattice-matched Zn_xCd_1-xTe buffers are known to reduce defects in Cd₃As₂ epilayers grown on GaAs and improve their electron mobility [1]. We find that the addition of a ZnTe nucleation layers is critical for stabilizing Cd₃As₂ (001) growth on GaAs (001) substrates, while Zn₃As₂ nucleation layers are required to remove tilt in the Zn_xCd_1-xTe buffer when growing on GaAs (110). These films have a much different morphology due to the higher surface energy, and also a much different dependence on arsenic incorporation compared to Cd₃As₂ (112). However, we show that the Cd₃As₂ epilayers exhibit electron mobilities greater than 10,000 cm²/V-s. Finally, we present a methodology for growing Cd₃As₂ (112) epilayers on GaAs (001) substrates using CdTe to switch between orientations [2], also allowing for integration with Si (001) [3]. Such schemes will allow for the design of Cd₃As₂ orientation for specific measurement and application needs.

This work was performed by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding was provided by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Division of Materials Sciences and Engineering, Physical Behavior of Materials Program under the Disorder in Topological Semimetals project.

[1] A. D. Rice, K. Park, E. T. Hughes, K. Mukherjee, K. Alberi. Phys. Rev. Mat. 3, 121201(R) (2019)

[2] A.D. Rice, J. Nelson, A.G. Norman, P. Walker, K. Alberi,High Mobility Cd₃As₂(112) on GaAs(001) Substrates Grown via Molecular Beam Epitaxy. ACS Appl. Electron. Mater.2022, 4, 729

[3] A.D. Rice, K. Alberi. Crystals2023, 13, 578.

Magnetic topological insulator could achieve quantum anomalous Hall (QAH) effect and spin-orbit torque (SOT) switching in the same structure. This is promising for its future applications in memory or switching with its robust surface properties by topologicalprotection.ConsideringthevanderWaalsnatureoftheepitaxiallayers,ithasveryweakvanderWaals bonding with the substrate. This gives rise to a novel quasi Van der Waals epitaxial growth mode attheinterfaceofGaAs(111) substratesand the epitaxiallayers, which has the advantages of both good crystallinity from substrate confinement, and a less influence from defects and roughness on the substrate surfaces. This is very crucial for achieving the quantization regime.

Inthisworkwehavedone hetero-epitaxy ofCr:(BixSb1-x)2Te3andother magnetic topological insulatorsonGaAs(111)substrates by MBE(MolecularBeamEpitaxy).Unlike the pure Van der Waals epitaxy which has more freedom at the interfaces epitaxial layer and substrates, we found out that inthisquasi Van der Waals growthmode,strain exist and relaxesquickly withinthe1^stepitaxiallayer. While the surface defects quickly get screened within the 1^st layer, the surface confinement also gives the epitaxial layer a uniform in-plane orientation which is important for achieving a single crystalline structure. Growthmechanismandtheinfluenceonitstransportproperties are also discussed.

Reflection high-energy electron diffraction (RHEED) data is a characterization technique used to monitor the real-time surface structure and material morphology during epitaxial growth. Analyzing RHEED data over the growth duration can reveal a wealth of information about the relationship between the structure of the growing material and the growth procedure. In practice, this information is difficult to access and frequently neglected because transforming RHEED data into physically interpretable information is challenging and time-consuming. This is especially true if the growth stage is rotating, an important step to synthesize materials at device-relevant length scales with uniform growth across the substrate. Existing strategies to deconvolute the rotational and intensity oscillation frequencies must be calibrated to the materials system and measurement conditions and are brittle to structural changes during growth. We present an automated, material system-agnostic, and parameter-free approach to analyze rotating RHEED data. Using an entire unlabeled RHEED video as input, we extract the rotational frequency as a function of time in the video and create a complementary dataset averaged over the rotational period. The averaged data is used as input to a series of unsupervised dimensional reduction and clustering algorithms to identify transition points in the growth independent of rotation. Within each growth segment identified between these transition points, we extract original RHEED patterns at high symmetry scattering angles and quantify them using image segmentation models. Transitions are validated using small, labeled datasets of expert-identified growth transitions. The metrics automatically extracted at these angles are compared with the equivalent angles throughout the growth to label and quantify the evolution of the materials system. We align these quantified pattern metrics with in-situ environmental metrology data, such as quenching temperature, to build correlations between synthesized material structure and process variables. Fusing domain knowledge with machine learning, we reduce the time and effort barriers to accessing all the physical information collected with RHEED, producing physically interpretable datasets on materials structure over the course of a rotating growth.