Spin-polarized voltage probes for helical edge state: A model study

Adak, Vivekananda; Roychowdhury, Krishanu; Das, Sourin

doi:10.1016/j.physe.2021.115125

Cited by 3 publications

(1 citation statement)

References 22 publications

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“…This is a time-reversal symmetric system with the edge modes having a conserved spin quantum number S z locked with their momentum, viz., if ↑ spins (S z = +1) flow along +k, ↓ spins (S z = −1) would flow along −k. These are known as the HESs having linear dispersions around the Γ point [30][31][32][33][34][35]. The HES of the QSHS are described by massless Dirac fermions where the Fermi sea carries a persistent spin current.…”

Section: Introductionmentioning

confidence: 99%

Spin-textured Volkov–Pankratov states and their tunnel magnetoresistance response

Adak,

Chakraborty,

Roychowdhury

et al. 2024

New J. Phys.

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Volkov-Pankratov (VP) states are a family of sub-gap states that appear at the smooth interface/domain wall between topologically distinct gapped states. We carry out quantum transport simulations on a 2D lattice model to demonstrate the emergence of such states in the edge spectrum of a quantum spin Hall system subjected to a smoothly varying exchange field that switches its sign at a given spatial point. We show the VP states possess non-trivial spin textures that can be characterized by a winding number in real space. It is further demonstrated that the application of an electric field along the edge provides control of this spin texture without altering the winding number. Finally, we illuminate how these spin textures can be read off via the local tunnel magnetoresistance (TMR) response of spin-polarized tunnel probes attached to the edge and the TMR can be controlled by purely electrical means akin to a Datta-Das type spin transistor.

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