Mapping the unconventional orbital texture in topological crystalline insulators

作者：Zeljkovic, Ilija; Okada, Yoshinori; Huang, Cheng Yi; Sankar, R; Walkup, Daniel; Zhou, Wenwen; Serbyn, Maksym; Chou, Fangcheng; Tsai, Wei Feng; Lin, Hsin; Bansil, A; Fu, Liang; Hasan, M Zahid; Madhavan, Vidya^*

来源：Nature Physics, 2014, 10(8): 572-577.

DOI：10.1038/NPHYS3012

The newly discovered topological crystalline insulators feature a complex band structure involving multiple Dirac cones(1-6), and are potentially highly tunable by external electric field, temperature or strain. Theoretically, it has been predicted that the various Dirac cones, which are offset in energy and momentum, might harbour vastly different orbital character(7). However, their orbital texture, which is of immense importance in determining a variety of a material's properties(8-10) remains elusive. Here, we unveil the orbital texture of Pb1-xSnxSe, a prototypical topological crystalline insulator. By using Fourier-transform scanning tunnelling spectroscopy we measure the interference patterns produced by the scattering of surface-state electrons. We discover that the intensity and energy dependences of the Fourier transforms show distinct characteristics, which can be directly attributed to orbital effects. Our experiments reveal a complex band topology involving two Lifshitz transitions(11) and establish the orbital nature of the Dirac bands, which could provide an alternative pathway towards future quantum applications.

• 出版日期2014-8
• 单位东北大学; 中山大学; MIT