2009/03/31 by Jianguo Wan, J. Wan, M. Cahay +3 · 42 citations
Chemistry · Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Asymmetry #Ballistic conduction #Chemistry #Condensed matter physics #Conductance #Electron #Magnetic field #Physics #Polarization (electrochemistry) #Quantum #Quantum and electron transport phenomena #Quantum mechanics #Quantum point contact #Quantum well #Semiconductor Quantum Structures and Devices #Spin polarization #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.80.155440
published in Physical Review B 80(15) (American Physical Society)
arxiv created 2009/08/26 · openalex publication_date 2009/10/19 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A nonequilibrium Green's function formalism is used to study the conductance of a side-gated quantum point contact (QPC) in the presence of the lateral spin-orbit coupling (LSOC). A small difference of bias voltage between the two side gates (SGs) leads to an inversion asymmetry in the LSOC between the opposite edges of the channel. In the single-electron modeling of transport, this triggers a spontaneous but insignificant spin polarization in the QPC. However, the spin polarization of the QPC is enhanced substantially when the effect of electron-electron interaction is included. The spin polarization is strong enough to result in the occurrence of a conductance plateau at 0.5G0 (G0=2e2/h) in the absence of any external magnetic field. In our simulations of a model QPC device, the 0.5 plateau is found to be quite robust and survives up to a temperature of 40 K. The spontaneous spin polarization and the resulting magnetization of the QPC can be reversed by flipping the polarity of the source to drain bias or the potential difference between the two SGs. These numerical simulations are in good agreement with recent experimental results for side-gated QPCs made from the low band-gap semiconductor InAs.