Abstract

A complete description of the spin response of 1D holes in quantum point contacts (QPCs) has remained an outstanding problem in spintronics. Despite this being a simple one-dimensional non-interacting problem, for 10 years no single theory has been been able to model the gzz >> g|| >> gperp form of the g-tensor seen time and again in Zeeman spin-splitting measurements on hole QPCs. However, newly developed theory from Dmitry Miserev et. al. on 1D holes in QPCs predicts that g|| is insensitive to Rashba, while gperp is highly sensitive. This model has successfully described the g-factor measured via Zeeman spin-splitting measurements for QPCs on quantum well (100) wafers [1], and is a promising candidate for explaining spin-behaviour in single heterojunction wafers with a strong Rashba field. In order to fully explore the effect of Rashba field on 1D holes, we are hoping to fabricate hole QPC devices on Cambridge wafer with an in-situ backgate in the very near future, which is an ongoing project with Dr. Joanna Waldie and the MBE growers at the Cavendish Laboratory. We have also started measuring Zeeman spin-splitting on p-type (111) GaAs wafer, where Rashba and Dresselhaus terms are predicted to anti-align and cause a suppression in the effective magnetic field, resulting in novel spin-behaviour [2].

[1] D. Miserev, et. al. arXiv:1612.00572 [cond-mat.mes-hall]

[2] L.Wang and M.W.Wu, Phys. Rev. B. 85, 235308 (2012)