论文标题
2D晶体中的田间可调拓扑相变和旋转式效应
Field-Tunable Topological Phase Transitions and Spin-Hall Effects in 2D Crystals
论文作者
论文摘要
随着2D晶体目录的最新添加，硅和其他硅级晶体目前正在研究并考虑用于新型设备应用中的许多独特特性。在本文中，我们研究了硅硅在磁场效应晶体管几何形状中的电子和运输特性。我们发现，可以通过垂直电场连续调节硅级晶体的浆果曲率。通过直接计算$ z_2 $不变的，我们确认当电场通过临界值时，从拓扑绝缘体到频带绝缘体发生了电子相变。在具有不对称栅极电压的设备设置中，此场可调浆果曲率会产生大型旋转电流横向到电荷电流。当电场强度超过临界值时，发现大型自旋电流会改变方向并大大减少。这一发现，可切换的自旋电流大量的发现表明，2D晶体的硅家族可能是可吸引现场可调式电荷旋转转换的有吸引力的候选者。拓扑不同阶段之间的这种场合可调相变可能也可用于稳健的Qubits。
As recent additions to the catalog of 2D crystals, silicene and other silicene-class crystals have numerous unique properties currently being investigated and considered for use in novel device applications. In this paper, we investigate electronic and transport properties of silicene in a field effect transistor geometry. We find that the Berry curvature of silicene-class crystals can be continuously tuned by a perpendicular electric field. By direct calculation of the $Z_2$ invariant, we confirm that an electronic phase transition from a topological insulator to a band insulator occurs when the electric field passes a critical value. In a device setting with asymmetric gate voltages, this field-tunable Berry curvature generates a large spin current transverse to the charge current. When the electric field strength surpasses the critical value, the bulk spin current is found to change direction and greatly decrease in magnitude. This finding of a large magnitude, switchable spin current suggests that the silicene family of 2D crystals could be an attractive candidate for field-tunable charge-spin conversion. Such field-tunable phase transitions between topologically distinct phases could be useful for robust qubits as well.
