Title: Symmetry-Driven Persistent Spin Texture Towards Ferromagnetic-free Non-Ballistic Spintronics

We have theoretically investigated symmetry and electronic properties of (110)- CdTe/ZnTe/MgTe zinc blende semiconductors and shown symmetry-driven momentum-independent uniform spin configuration known as persistent spin texture (PST) at the Brillouin zone centre. [1,2] The atomic arrangement in this facet exhibits a unique combination of three basic symmetries found in nature: rotation, reflection, and translation which makes them nonsymmorphic in nature. PST originating from in-plane ferroelectricity coupled with strong spin-orbit coupling induces a unidirectional out-of-plane Rashba spin-orbit field (SOF). PST in these structures is found to be robust against external perturbations such as strain, structural distortion and independent of layer thickness. These unprecedented intrinsic spin transport properties hold utmost importance in spintronics as the experimental stringent condition of equal Rashba and Dresselhaus constants is eliminated. PST originating from crystal symmetry makes an ideal alternative to quantum well structures. Further, these materials exhibit finite spin-Hall conductivity (SHC) at the band edges and, hence, can be used in ferromagnet-free spin-Hall transistors.