Nontrivial topological valence bands of common diamond and zinc-blende semiconductors

Abstract

The diamond and zinc-blende semiconductors are well-known and have been widely studied for decades. Yet, their electronic structure still surprises with unexpected topological properties of the valence bands. In this joint theoretical and experimental investigation we demonstrate for the benchmark compounds InSb and GaAs that the electronic structure features topological surface states below the Fermi energy. Our parity analysis shows that the spin-orbit split-off band near the valence band maximum exhibits a strong topologically non-trivial behavior characterized by the Z2 invariants (1; 000). The non-trivial character emerges instantaneously with non-zero spin-orbit coupling, in contrast to the conventional topological phase transition mechanism. Ab initio-based tight-binding calculations resolve topological surface states in the occupied electronic structure of InSb and GaAs, further confirmed experimentally by soft X-ray angle-resolved photoemission from both materials. Our findings are valid for all other materials whose valence bands are adiabatically linked to those of InSb, i.e., many diamond and zinc-blende semiconductors, as well as other related materials, such as half-Heusler compounds. arXiv:1904.05063v1 [cond-mat.mtrl-sci]

Revisiting the physical origin and nature of surface states in inverted-band semiconductors

“…They still can be detected with the ARPES experiments at small 2D momenta along the interface where the overlap of these states with heavy holes is weak, see Refs. [31,38]. The results obtained by us can be used for the correct interpretation of the current and future experiments with materials such as α-Sn and HgTe.…”

“…(We should mention, however, that at small k y , at which the overlap of these states with heavy holes is weak, they can be detected with the ARPES experiments, see Refs. [31,38].) On the other hand, the surface states lying in the projected gap between the light-hole and heavy-hole bands found in Ref.…”