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1. Epitaxial growth of cubic WC (001) on MgO(001)

   https://doi.org/10.1016/j.jallcom.2020.158403  

   Fang, Peijiao; Wang, Baiwei; Mulligan, C.P.; Murray, T.M.; Khare, S.V.; Gall, Daniel (April 2021, Journal of Alloys and Compounds)

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2. Electron scattering at interfaces in epitaxial W(001)–Mo(001) multilayers

   https://doi.org/10.1063/5.0223176  

   Shen, Poyen; Gall, Daniel (August 2024, Journal of Applied Physics)

   Epitaxial W–Mo multilayers are employed as a model system to demonstrate how resistivity measurements parallel to metal–metal interfaces can be used to quantify the specific interface resistance without sub-10-nm patterning that would be required for direct transport measurements across the interface. 50-nm-thick epitaxial multilayer stacks containing 2–60 individual W(001) and Mo(001) layers are deposited on MgO(001) substrates and their resistivity ρ measured as a function of superlattice period Λ at 293 and 77 K. The measured room temperature ρ increases from 7.10 to 8.62 μΩ cm with decreasing Λ = 50–1.7 nm, which is attributed to the increasing electron-interface scattering. The semiclassical Fuchs–Sondheimer model for surface scattering dramatically overestimates the resistivity, which is attributed to coherent electron transmission across multiple interfaces. A new Boltzmann transport model treats each interface as a boundary condition where electrons either scatter diffusely or traverse without momentum loss with a probability T for the first encountered interface and with 100% transmission at subsequent interfaces until they are relaxed by a bulk scattering event. This model has a single unknown parameter T, which becomes the fitting parameter for experimental data analysis, yielding a temperature-independent T = 0.8 ± 0.1 and a corresponding contact resistance at the W(001)–Mo(001) interface of 2.6 × 10−16 Ω m2. 

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3. MnO(001) thin films on MgO(001) grown by reactive MBE using supersonic molecular beams

   https://doi.org/10.1063/5.0198832  

   Pedersen, Andrew J; Liu, Junchen; Li, Fanxing; Lamb, H Henry (April 2024, The Journal of Chemical Physics)

   MnO(001) thin films were grown on commercial MgO(001) substrates at 520 °C by reactive molecular beam epitaxy (MBE) using Mn vapor and O2-seeded supersonic molecular beams (SMBs) both with and without radio frequency (RF) plasma excitation. For comparison, MnO(001) films were grown by reactive MBE using O2 from a leak valve. X-ray photoelectron spectroscopy confirmed the Mn2+ oxidation state and 10%–15% excess oxygen near the growth surface. Reflection high-energy electron diffraction and x-ray diffraction evidenced that the films were rock salt cubic MnO with very strong (001) orientation. High-angle annular dark field scanning transmission electron microscopy with energy-dispersive x-ray spectroscopy demonstrated abrupt MnO/MgO interfaces and indicated [(001)MnO||(001)MgO] epitaxial growth. Ex situ atomic force microscopy of films deposited without RF excitation revealed smooth growth surfaces. An SMB-grown MnO(001) film was converted to Mn3O4 with strong (110) orientation by post-growth exposure to an RF-discharge (RFD) SMB source providing O atoms; the surface of the resultant film contained elongated pits aligned with the MgO110 directions. In contrast, using the RFD-SMB source for growth resulted in MnO(001) films with elongated growth pits and square pyramidal hillocks aligned along the MgO110 and 100 directions, respectively. 

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4. Conductive surface oxide on CrN(001) layers

   https://doi.org/10.1063/1.5091034  

   McGahay, Mary E.; Gall, Daniel (April 2019, Applied Physics Letters)
5. Electron Scattering at Epitaxial Ni(001) Surfaces

   https://doi.org/10.1109/TED.2019.2934636  

   Milosevic, Erik; Zheng, Pengyuan; Gall, Daniel (October 2019, IEEE Transactions on Electron Devices)