Strains induce vector potentials in square buckled Rashba Lead Chalcogenides

Recently, we have found a new class of two-dimensional (2D) ferroelectric Rashba semiconductors (FERSC) PbX (X=S, Se, Te) with tunable spin-orbitronic properties [1]. Our first-principles calculations, together with tight binding (TB) models, provide a framework to understand and design this new class of materials. One of the exciting features of many 2D materials is the tunability of their electronic and optical properties through strain engineering. Based on our previous TB results, we derive an effective low-energy Hamiltonian around the symmetry points that captures the effects of strains on the electronic properties of PbX. We find that strains induce vector potentials which shift the Dirac point and also induce anisotropy in the Rashba parameter. This effect is equivalent to application of an in-plane magnetic field. This finding will be important to understand the variations in local Rashba parameters in the real space due to effects caused by substrates and defects.

Reference:
[1] P. Z. Hanakata, A. S. Rodin, A. Carvalho, H. S. Park, D. K. Campbell, A.H. C. Neto, Physical Review B 96, 161401(R) (2017)