npj: 二维电子气为纳米自旋器件铺平道路

海归学者发起的公益学术平台

分享信息，整合资源

交流学术，偶尔风月

近日发表在npj Computational Materials的一项最新研究表明，一种新颖的纳米自旋电子三级管可以在室温下工作。来自中国台湾清华大学的T. H. Wang和H. T. Jeng通过第一性原理计算，证实一种理想的二维电子气可在MoTe2半导体基底上生长的绝缘体硒化铋超薄膜上实现，而这种理想的二维电子气是半导体自旋电子器件实现应用的关键。该超薄器件中形成的二维电子气表现出大的“自旋分裂”现象，即两种状态的电子自旋间的分离，而这正是类三极管器件所必须的性质。电子自旋器件基于电子固有的自旋特性，而不象当前常规电子器件所依靠的电荷特性，因而可以在更小的空间内存储更多的数据，消耗更少的电能，使用更便宜的材料，为未来电子器件带来革命性的变化。

论文近日发表于npj Computational Materials，文末“阅读原文”可以自由下载。其标题与摘要如下：

Wide-range ideal 2D Rashba electron gas with large spin splitting in Bi2Se3/MoTe2 heterostructure

Te-Hsien Wang & Horng-Tay Jeng

An application-expected ideal two-dimensional Rashba electron gas, i.e., nearly all the conduction electrons occupy the Rashba bands, is crucial for semiconductor spintronic applications. We demonstrate that such an ideal two-dimensional Rashba electron gas with a large Rashba splitting can be realized in a topological insulator Bi2Se3 ultrathin film grown on a transition metal dichalcogenides MoTe2 substrate through first-principle calculations. Our results show the Rashba bands exclusively over a very large energy interval of about 0.6 eV around the Fermi level within the MoTe2 semiconducting gap. Such a wide-range ideal two-dimensional Rashba electron gas with a large spin splitting, which is desirable for real devices utilizing the Rashba effect, has never been found before. Due to the strong spin–orbit coupling, the strength of the Rashba splitting is comparable with that of the heavy-metal surfaces such as Au and Bi surfaces, giving rise to a spin precession length as small as ~10 nm. The maximum in-plane spin polarization of the inner (outer) Rashba band near the Γ point is about 70% (60%). The room-temperature coherence length is at least several times longer than the spin precession length, providing good coherency through the spin processing devices. The wide energy window for ideal Rashba bands, small spin precession length, as well as long spin coherence length in this two-dimensional topological insulator/transition metal dichalcogenides heterostructure pave the way for realizing an ultrathin nano-scale spintronic device such as the Datta–Das spin transistor at room-temperature.

原文链接：http://www.nature.com/articles/s41524-017-0011-5

扩展阅读

 

欢迎广大学者供稿，报道最新研究成果投稿、授权、合作事宜请联系

[e-mail] 或微信ID: scholarset

回复“目录”或“分类”，浏览知社更多精华。长按二维码识别，可以关注/进入公众号进行回复。