Connection topology of step edge state bands at the surface of a three dimensional topological insulator

Abstract

Topological insulators (TIs) in the Bi 2 Se 3 family manifest helical Dirac surface states that span the topologically ordered bulk band gap. Recent scanning tunneling microscopy measurements have discovered additional states in the bulk band gap of Bi 2 Se 3 and Bi 2 Te 3 , localized at one-dimensional step edges. Here numerical simulations of a TI surface are used to explore the phenomenology of edge state formation at the single-quintuple layer step defects found ubiquitously on these materials. The modeled one-dimensional edge states are found to exhibit a stable topological connection to the twodimensional surface state Dirac point.

Spectromicroscopic measurement of surface and bulk band structure interplay in a disordered topological insulator

“…Topological insulators are bulk semiconductors that manifest in-gap massless Dirac surface states due to the topological bulk-boundary correspondence principle [1][2][3]. These surface states have been a subject of tremendous ongoing interest, due both to their intrinsic properties and to higher order emergence phenomena that can be achieved by manipulating the interface environment [4][5][6][7][8][9][10][11]. Here, ARPES spectromicroscopy and supplementary scanning tunneling microscopy (STM) are performed on the model topological insulator Bi 2 Se 3 to investigate the interplay of crystallographic inhomogeneity with the topologically ordered bulk and surface band structure.…”

“…The three-dimensional topological insulator (TI) state in Bi 2 Se 3 was identified in 2008 [12,13] and features a large bulk band gap of ~0.3eV, spanned by a relatively ideal Dirac cone surface state. Though the existence of the surface state is protected by topology, the symmetries and band dispersion of surface state electrons can be strongly influenced by crystallographic defects, potentially including the emergence of new quasiparticles [7][8][9][10][11][14][15][16][17][18].…”

Experimental Observation of Bound States of 2D Dirac Electrons at Surface Steps of the Topological Insulator Bi2Se3

“…Other theoretical approaches include treating the step as a δ ‐function potential barrier . A barrier potential at the step results in bound states formation, but branches of point in the opposite direction compared to the states in a potential well discussed here.…”

“…Topologically nontrivial systems offer another extensive playground for studying exotic quasiparticle physics. Steps on the surface of topological insulators are interesting objects of experimental as well as theoretical investigation. Edge states were found on steps in weak and crystalline topological insulators and Weyl semimetals .…”

“…Steps on the surface of topological insulators are interesting objects of experimental [19][20][21][22][23][24][25] as well as theoretical [8,9,18,[26][27][28][29][30][31][32][33][34] investigation. Edge states were found on steps in crystalline topological insulators [35] and Weyl semimetals [36][37][38].…”