Observation of Dirac cone warping and chirality effects in silicene

TL;DR

This study reveals hexagonal warping and chirality effects of Dirac fermions in silicene on Ag(111), using STM/STS and density functional theory, highlighting silicene's unique electronic properties compared to graphene.

Contribution

It provides the first direct observation of Dirac cone warping and chirality effects in silicene, supported by experimental STM/STS data and theoretical calculations.

Findings

Dirac Fermion chirality confirmed through QPI decay patterns

Hexagonal Dirac cone warping observed in silicene

Density functional calculations support experimental results

Abstract

We performed low temperature scanning tunneling microscopy (STM) and spectroscopy (STS) studies on the electronic properties of (R3xR3)R30{\deg} phase of silicene on Ag(111) surface. We found the existence of Dirac Fermion chirality through the observation of -1.5 and -1.0 power law decay of quasiparticle interference (QPI) patterns. Moreover, in contrast to the trigonal warping of Dirac cone in graphene, we found that the Dirac cone of silicene is hexagonally warped, which is further confirmed by density functional calculations and explained by the unique superstructure of silicene. Our results demonstrate that the (R3xR3)R30{\deg} phase is an ideal system to investigate the unique Dirac Fermion properties of silicene.