通过在外延掺杂拓扑晶体绝缘体 Pb1-xSnxSe 的表面能带诱导 Lifshitz 转变。

Inducing a Lifshitz transition by extrinsic doping of surface bands in the topological crystalline insulator Pb1-xSnxSe.

机构信息

Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.

Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.

出版信息

Phys Rev Lett. 2014 Apr 11;112(14):146403. doi: 10.1103/PhysRevLett.112.146403. Epub 2014 Apr 10.

DOI:10.1103/PhysRevLett.112.146403

PMID:24765995

Abstract

The narrow gap semiconductor Pb1-xSnxSe was investigated for topologically protected surface states in its rocksalt structural phase for x=0.45, 0.23, 0.15, and 0. Angle-resolved photoelectron spectroscopy of intrinsically p-doped samples showed a clear indication of two Dirac cones, eccentric about the time-reversal invariant point X¯ of the surface Brillouin zone for all but the x=0 sample. Adsorption of alkalies gradually filled the surface bands with electrons, driving the x>0 topological crystalline insulator systems through Lifshitz transitions, and from a holelike to electronlike Fermi surface. The electron-doped bands in x>0 samples exhibited the full configuration of the Dirac cones, also confirming electron-hole symmetry of the surface bands.

摘要

窄带隙半导体 Pb1-xSnxSe 在其岩盐结构相中进行了拓扑保护表面态的研究，x 值分别为 0.45、0.23、0.15 和 0。对于本征 p 型掺杂样品，角分辨光电子能谱清楚地表明，除了 x=0 样品之外，所有样品的表面布里渊区时间反演不变点 X¯附近都有两个狄拉克锥，而且是偏心的。对于所有碱金属的吸附，逐渐用电子填充表面能带，使 x>0 的拓扑晶体绝缘体系统通过 Lifshitz 转变，并从类空穴到类电子的费米面。x>0 样品中的电子掺杂能带表现出了狄拉克锥的完整配置，也证实了表面能带的电子空穴对称性。