Hydrogenated group-IV binary monolayers: a new family of inversion-asymmetric topological insulators

Abstract

Band topology and Rashba spin splitting (RSS) are two extensively explored exotic properties in condensed matter physics.

Conductance fluctuations of monolayer GeSnH2 in the topological phase using a low-energy effective tight-binding Hamiltonian

“…Thus, the unit cell of GeSnH 2 consists of four atoms: one Ge, one Sn, and two hydrogen atoms that are right above (below) the Ge (Sn) atoms. The lattice translation vectors are a 1,2 = a( √ 3/2ŷ ± 1/2x) with the lattice constant a = 4.41 Å and the buckling height (h) is 0.76 Å [11,12]. Note that the x and y axes are taken to be along the armchair and zigzag directions, respectively; and the z axis is in the normal direction to the plane of the GeSnH 2 film.…”

“…The DFT calculations including spin-orbit interaction predicted that a topological phase transition is induced in ML GeSnH 2 through the application of biaxial in-plane tensile strain. It was shown that the low-energy electronic structure of ML GeSnH 2 is determined exclusively by using s, p x , and p y atomic orbitals of Ge and Sn atoms [11,12]. However, in order to examine the effect of random disorder on the electronic properties of this system and to confirm the topological nature of the phase transition, large system sizes are required.…”

“…In a previous work we have studied GeCH 3 which is an inversion symmetric TI under strain [10]. Inversion asymmetry introduces many additional intriguing properties in TIs such as pyroelectricity, * fazileh@cc.iut.ac.ir crystalline-surface-dependent topological electronic states, natural topological p-n junctions, and topological magnetoelectric effects [11][12][13]. Therefore, 2D IATI materials that are stable at room temperature would be highly promising candidates for future spintronics and quantum computing applications.…”

Topological phase transition in GeSnH$_2$ induced by biaxial tensile strain: A tight-binding study

“…Thus, the unit cell of GeSnH 2 consists of four atoms: one Ge, one Sn, and two Hydrogen atoms that are right above (below) the Ge (Sn) atoms. The lattice translation vectors are a 1,2 = a( √ 3/2ŷ ± 1/2x) with the lattice constant a = 4.41 Åand the buckling height (h) is 0.76 Å [10,11]. Note that the x and y axes are taken to be along the armchair and zigzag directions, respectively; and the z axis is in the normal direction to the plane of the GeSnH 2 film.…”

“…In terms of crystal structure, TIs can be generally divided into inversion-symmetric TIs (ISTIs) and inversionasymmetric TIs (IATIs). Inversion asymmetry introduces many additional intriguing properties in TIs such as pyroelectricity, crystalline-surface-dependent topological electronic states, natural topological p-n junctions, and topological magneto-electric effects [10][11][12]. Therefore, 2D IATI materials that are stable at room temperature would be highly promising candidates for future spintronics and quantum computing applications.…”