Tunneling spin current in a system with spin degeneracy

Abstract

We study theoretically spin current generation from a band insulator with PT symmetry, which is associated with Zener tunneling in strong dc electric fields. Each band in this system is doubly degenerate with opposite spins, but spin rotational symmetry is not preserved in general. We consider the condition for spin current generation in connection with the nature of the wave function, which ultimately depends on a geometric quantity known as the shift vector. From an analysis of a two-band model, we find that the shift vector is necessary for spin current generation in a PT symmetric system. We also present zigzag chain models that have shift vectors, and confirm from numerical calculations that a nonzero tunneling spin current occurs in spin-degenerate systems.

15 pages, 8 figures

References in corpus (7)

• Dissipationless Quantum Spin Current at Room Temperature
• Multipole classification in 122 magnetic point groups for unified understanding of multiferroic responses and transport phenomena
• Nonlinear spin current generation in noncentrosymmetric spin-orbit coupled systems
• Uncovering and tailoring hidden Rashba spin-orbit splitting in centrosymmetric crystals
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