Reversible spin texture in ferroelectric HfO2

Authors

• L. L. Tao, University of Nebraska-LincolnFollow
• Tula R. Paudel, University of Nebraska-LincolnFollow
• Alexey Kovalev, University of Nebraska - LncolnFollow
• Evgeny Tsymbal, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

6-2017

Citation

PHYSICAL REVIEW B 95, 245141 (2017)

DOI: 10.1103/PhysRevB.95.245141

Comments

Copyright © 2017 American Physical Society. Used by permission.

Abstract

Spin-orbit coupling effects occurring in noncentrosymmetric materials are known to be responsible for nontrivial spin configurations and a number of emergent physical phenomena. Ferroelectric materials may be especially interesting in this regard due to reversible spontaneous polarization making possible a nonvolatile electrical control of the spin degrees of freedom. Here, we explore a technologically relevant oxide material, HfO2, which has been shown to exhibit robust ferroelectricity in a noncentrosymmetric orthorhombic phase. Using theoretical modelling based on density-functional theory, we investigate the spin-dependent electronic structure of the ferroelectric HfO2 and demonstrate the appearance of chiral spin textures driven by spin-orbit coupling. We analyze these spin configurations in terms of the Rashba and Dresselhaus effects within the k · p Hamiltonian model and find that the Rashba-type spin texture dominates around the valence-band maximum, while the Dresselhaus-type spin texture prevails around the conduction band minimum. The latter is characterized by a very large Dresselhaus constant λD = 0.578 eV A° , which allows using this material as a tunnel barrier to produce tunneling anomalous and spin Hall effects that are reversible by ferroelectric polarization.