The conductance of a GaAs-based suspended quantum point contact (QPC) equipped with lateral side gates has been experimentally studied in the absence of the external magnetic field. The half-integer conductance plateau ($0.5\times 2e^2/h$) has been observed when an asymmetric voltage between the side gates is applied. The appearance of this plateau has been attributed to the spin degeneracy lifting caused by the spin-orbit coupling associated with the lateral electric field in the asymmetrically biased QPC. We have experimentally demonstrated that, despite the relatively small g-factor in GaAs, the observation of the spin polarization in the GaAs-based QPC became possible after the suspension due to the enhancement of the electron-electron interaction and the effect of the electric field guiding. These features are caused by a partial confinement of the electric field lines within a suspended semiconductor layer with a high dielectric constant.

中文翻译：

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悬浮GaAs量子点接触中的横向电场诱导的自旋极化

在没有外部磁场的情况下，已经通过实验研究了配备有侧面栅极的基于GaAs的悬浮量子点接触（QPC）的电导率。半整数电导平台（$0.5\times \mathrm{2个}{Ë}^{\mathrm{2个}}/H$当在侧栅极之间施加不对称电压时，已经观察到）。该平稳期的出现归因于与非对称偏置QPC中与横向电场相关的自旋轨道耦合引起的自旋简并性提升。我们已经通过实验证明，尽管GaAs中的g因子相对较小，但由于电子-电子相互作用的增强和电场的影响，在悬浮后，仍可以在基于GaAs的QPC中观察自旋极化指导。这些特征是由于电场线在具有高介电常数的悬浮半导体层内的部分限制而引起的。