ARPES study of the epitaxially grown topological crystalline insulator SnTe(111)

TL;DR

This study uses angle-resolved photoemission spectroscopy to investigate the surface and bulk electronic structures of epitaxially grown SnTe(111), a topological crystalline insulator, revealing Dirac cones at specific surface and bulk points.

Contribution

First direct ARPES measurement of the (111) surface of epitaxial SnTe revealing surface and bulk Dirac cones with detailed energy and momentum characteristics.

Findings

Observation of Dirac cones at surface Gamma_bar and M_bar points.

Detection of a Dirac-like band structure at the bulk Gamma point.

Distinct Dirac energies at surface and bulk locations.

Abstract

SnTe is a prototypical topological crystalline insulator, in which the gapless surface state is protected by a crystal symmetry. The hallmark of the topological properties in SnTe is the Dirac cones projected to the surfaces with mirror symmetry, stemming from the band inversion near the L points of its bulk Brillouin zone, which can be measured by angle-resolved photoemission. We have obtained the (111) surface of SnTe film by molecular beam epitaxy on BaF2(111) substrate. Photon-energy-dependence of in situ angle-resolved photoemission, covering multiple Brillouin zones in the direction perpendicular tothe (111) surface, demonstrate the projected Dirac cones at the Gamma_bar and M_bar points of the surface Brillouinzone. In addition, we observe a Dirac-cone-like band structure at the Gamma point of the bulk Brillouin zone,whose Dirac energy is largely different from those at the Gamma_bar and M_bar points.