65 Influence of Impurity and Dangling Bond Scattering on the Conductance Anomalies of Side-Gated Quantum Point Contacts

摘要

For more than a decade, there have been many experiments reporting anomalies that appear at noninteger values of the quantized conductance G_0 in the ballistic conductance regime of quantum point contacts (QPCs) based on GaAs. These include the observation of an anomalous plateau at G ? 0.5 G_0 [1–4] and the well-known "0.7 structure" [5]. The majority of the theoretical models link them to spontaneous spin polarization in the QPC [6–8]. Recently, we used a nonequilibrium Green's function (NEGF) approach to study in detail the ballistic conductance of asymmetrically biased, side-gated QPCs in the presence of lateral spin–orbit coupling (LSOC) and strong electron– electron interactions. We performed simulations for a wide range of QPC dimensions and gate bias voltages [9].