单晶α-Sn薄膜的外延生长及输运性质研究进展

Research Progress on Epitaxial Growth and Transport Property of Single Crystalα-Sn Films

α-Sn(灰锡)是一种重要的拓扑材料,据理论预测,打破α-Sn的对称性可以得到拓扑绝缘体、拓扑半金属等多种拓扑相。目前α-Sn的研究以理论计算和角分辨光电子能谱研究能带结构为主,受限于衬底条件,高质量的α-Sn外延生长及其电输运性质的研究较少。本文结合课题组近几年在α-Sn薄膜外延生长和拓扑输运性质方面的研究进展,系统地综述了高质量单晶α-Sn薄膜的分子束外延生长、电输运的测试方法及拓扑性质的验证。通过对输运性质的研究证实了α-Sn的狄拉克半金属相和自旋极化拓扑表面态,进一步通过改变薄膜厚度和外加应力的方式来实现α-Sn拓扑性质的调控。以上工作不仅为进一步研究α-Sn的拓扑性质提供了重要依据,也为基于α-Sn的新型量子器件研究提供了重要的材料基础。

As an important topological material,α-Sn(also known as grey tin)can be turned into many topological phases including topological insulator and topological semimetal by breaking its symmetry.Until now,the study onα-Sn has been mainly focused on the topological band structures by theorical calculation and angle resolved photoemission spectroscopy(ARPES),while the epitaxial growth ofα-Sn and its electronic transport properties are seldom reported due to the substrate contribution.In this paper,the research progress ofα-Sn is reviewed based on the recent progress made by our group,including the epitaxial growth of high qualityα-Sn films by molecular beam epitaxy(MBE),the methodology of transport measurements and topological property investigation.The transport evidence of topological semimetal phase and spin-polarized topological surface state inα-Sn is demonstrated and the topological property is engineered by thickness and strain,etc.This work provides not only important evidences for further investigation on the topological property ofα-Sn,but also an essential material platform for novel quantum devices based onα-Sn.