g-factor and well-width fluctuations as a function of carrier density in the two-dimensional hole accumulation layer of transfer-doped diamond

g-factor and well-width fluctuations as a function of carrier density in the two-dimensional hole accumulation layer of transfer-doped diamond, Akhgar, Golrokh and Ley, Lothar and Creedon, Daniel L. and Stacey, Alastair and McCallum, Jeffrey C. and Hamilton, Alex R. and Pakes, Christopher I., Physical Review B, 99, 3, 035159, 2019, https://doi.org/10.1103/PhysRevB.99.035159

The two-dimensional (2D) hole gas at the surface of transfer-doped diamond shows quantum-mechanical interference effects in magnetoresistance in the form of weak localization and weak antilocalization (WAL) at temperatures below about 5 K. Here we use the quenching of the WAL by an additional magnetic field applied parallel to the 2D plane to extract the magnitude of the in-plane g-factor of the holes and fluctuations in the well width as a function of carrier density. Carrier densities are varied between 1.71 and 4.35×1013cm-2 by gating a Hall bar device with an ionic liquid. Over this range, calculated values of |g| vary between 1.6 and 2.3 and the extracted well-width variation drops from 3 to 1.3 nm rms over the phase coherence length of 33 nm for a fixed geometrical surface roughness of about 1 nm as measured by atomic force microscopy. Possible mechanisms for the extracted variations in the presence of the ionic liquid are discussed.