High-field magnetotransport studies of surface-conducting diamonds

Abstract

The observation of a strong and tunable spin-orbit interaction (SOI) in surface-conducting diamond opens up a new avenue for building diamond-based spintronics. Herein we provide a comprehensive method to analyze the magnetotransport behavior of surface-conducting hydrogen-terminated diamond (H-diamond) Hall bar devices and $\mathrm{Al}/{\mathrm{Al}}_{2}{\mathrm{O}}_{3}/{\mathrm{V}}_{2}{\mathrm{O}}_{5}/\mathrm{H}$-diamond metal-oxide semiconductor field-effect transistors, respectively. By adopting a significantly improved theoretical magnetotransport model, the reduced magnetoconductance can be accurately explained both within and outside the quantum diffusive regime. The model is valid for all doping strategies of surface-conducting diamond tested. From this analysis, we find that the orbital magnetoresistance, a classical effect distinct from the SOI, dominates the magnetotransport in surface-conducting diamond at high magnetic fields. Furthermore, local hole mobilities as high as $1000\text{--}3000\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}/\mathrm{V}\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}\mathrm{s}$ have been observed in this work, indicating the possibility of diamond-based electronics with ultrahigh hole mobilities at cryogenic temperatures.