(110) Facet of MgTe Zinc Blende Semiconductor: A Holy Grail for Modern Spintronics

Abstract

Unlike, momentum-dependent Rashba spin-splitting, materials exhibiting intrinsic momentum-independent unidirectional spin polarization also known as persistent spin texture (PST) in the full Brillouin zone are scarce. In this work, a list of characteristic electronic properties for identifying an ideal PST material is provided based on earlier analytical models, and a new semiconductor, the MgTe(110) facet is proposed which satisfies all these conditions and exhibits PST in the full Brillouin zone. The atomic arrangement in this particular facet exhibits three basic symmetries found in nature: rotation, reflection, and translation. Using the method of invariance, an effective Hamiltonian is constructed which reproduces the results obtained using the density functional theory. Further, mono/few layers of MgTe (110) facets of the zinc-blende structure are proposed for a ferromagnet-free non-ballistic spin-field effect transistor (s-FET) that combines both the spin-Hall effect and inverse spin-Hall effect, thus harmonizing spintronics with conventional electronics. Although only quantum well structures have been experimentally studied for nonballistic s-FET under the stringent condition of equal Rashba and Dresselhaus strength, PST originating intrinsically in the proposed 2D structures makes them an ideal alternate.