界面调控常规半导体拓扑绝缘体相变

项目名称： 界面调控常规半导体拓扑绝缘体相变

项目编号： No.11504366

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 张东

作者单位： 中国科学院半导体研究所

项目金额： 20万元

中文摘要： 近年来拓扑绝缘体引起了凝聚态物理学领域浓厚的研究兴趣。拓扑绝缘体在下一代自旋电子学器件的应用可能受到两大因素的制约：一则因为自旋轨道耦合打开的反转带隙较小，易受热扰动湮没，二则因为组成拓扑绝缘体的元素一般丰度较低，可能难于广泛应用。本项目旨在通过合理的界面设计把常规半导体驱动到拓扑绝缘体相。关键在于利用半导体异质结与超晶格极性界面处的电荷积累，同时辅以界面应力调制等手段，以获得极强的内建电场。 这一内建电场可以反转常规半导体能带顺序，并显著增强Rashba自旋轨道耦合强度，从而实现传统常规半导体的拓扑绝缘体转变。

中文关键词： 拓扑绝缘体；量子自旋霍尔效应；自旋轨道耦合；半导体界面与异质结；极化电场

英文摘要： Topological insulators have aroused enormous interests for its unique electronic structures. However, the application of topological insulators in future spintronics is currently restricted by the small spin-orbital coupling induced bandgap and the rare abundance of the elements. An alternative way is to drive commonly-used semiconductors into topological insulator phases. In this application, we construct direct bandgaped semiconductor heterostructures and superlattices by rational design. Accompanied with interface strain manipulation, the strong intrinsic polarized electric field induced by the charge accumulation in each interface will invert the bandgap, generate large Rashba spin-orbit coupling effect and finally drive commonly-used semiconductors into topological insulators. In order to accurately describe this topological phase transition, we will develop a fast and efficient electronic structures calculation code based on the state-of-arts first-principles calculations.

英文关键词： Topological insulators;Quantum Spin Hall Effect;Spin-orbital coupling;Semiconductor Interfaces and Heterostructures;Polarized Electrostatic Field