Driving ultrafast spin and energy modulation in quantum well states via photo-induced electric fields
Driving ultrafast spin and energy modulation in quantum well states via photo-induced electric fields
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DOI：
10.1038/s41535-022-00490-2
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发表时间：
2022-08-15
影响因子：
5.7
通讯作者：
Lanzara，Alessandra
中科院分区：
文献类型：
--
作者：
Ciocys，Samuel T.;Maksimovic，Nikola;Lanzara，Alessandra
现代光电子和自旋电子器件的未来取决于我们在超快时间尺度上控制自旋和电荷自由度的能力。Rashba自旋分裂量子阱态是在强自旋轨道耦合材料表面形成的二维态，由于其能量和自旋态的可调性，是理想的。然而，到目前为止，大多数研究只是以静态的方式证明了这种控制。在这项研究中，我们证明了Bi2Se3at皮秒时间尺度上表面量子阱态的自旋和能量自由度的控制。通过聚焦激光脉冲，我们调制带弯曲，在材料表面产生皮秒的时变电场，从而可逆地调制量子阱光谱和拉什巴效应。此外，我们发现了一个动态的准费米能级，它依赖于第二量子阱带底的利夫希茨跃迁。这些结果为具有超快电子相位开关的光驱动自旋电子器件开辟了一条途径，并为将这种超快光门控技术扩展到更广泛的二维材料提供了有趣的前景。
The future of modern optoelectronics and spintronic devices relies on our ability to control the spin and charge degrees of freedom at ultrafast timescales. Rashba spin-split quantum well states, 2D states that develop at the surface of strong spin-orbit coupling materials, are ideal given the tunability of their energy and spin states. So far, however, most studies have only demonstrated such control in a static way. In this study, we demonstrate control of the spin and energy degrees of freedom of surface quantum well states on Bi2Se3at picosecond timescales. By means of a focused laser pulse, we modulate the band-bending, producing picosecond time-varying electric fields at the material’s surface, thereby reversibly modulating the quantum well spectrum and Rashba effect. Moreover, we uncover a dynamic quasi-Fermi level, dependent on the Lifshitz transition of the second quantum well band bottom. These results open a pathway for light-driven spintronic devices with ultrafast switching of electronic phases, and offer the interesting prospect to extend this ultrafast photo-gating technique to a broader host of 2D materials.