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Title: Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators

Authors:
;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1341918
Grant/Contract Number:
FG02-05ER46225
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 4; Related Information: CHORUS Timestamp: 2017-02-01 10:46:25; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Van Dyke, John S., and Morr, Dirk K.. Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.045151.
Van Dyke, John S., & Morr, Dirk K.. Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators. United States. doi:10.1103/PhysRevB.95.045151.
Van Dyke, John S., and Morr, Dirk K.. Mon . "Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators". United States. doi:10.1103/PhysRevB.95.045151.
@article{osti_1341918,
title = {Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators},
author = {Van Dyke, John S. and Morr, Dirk K.},
abstractNote = {},
doi = {10.1103/PhysRevB.95.045151},
journal = {Physical Review B},
number = 4,
volume = 95,
place = {United States},
year = {Mon Jan 30 00:00:00 EST 2017},
month = {Mon Jan 30 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.95.045151

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  • The spin filtering of electrons tunneling from the edge states of a two-dimensional topological insulator into a normal conductor under a magnetic field (external or induced due to proximity to a magnetic insulator) is studied. Calculations are performed for a tunnel contact of finite length between the topological insulator and an electronic multimode quantum strip. It is shown that the flow of tunneling electrons is split in the strip, so that spin-polarized currents arise in its left and right branches. These currents can be effectively controlled by the contact voltage and the chemical potential of the system. The presence ofmore » a magnetic field, which splits the spin subbands of the electron spectrum in the strip, gives rise to switching of the spin current between the strip branches.« less
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  • We present the novel topological tensor currents to describe the infinitesimal thin higher-dimensional topological defects in the local SO(n) gauge theory. The topological quantization of defects and the inner structure of the currents are obtained. As the generalization of Nielsen-Olesen local U(1) field theory for Nambu string, the local SO(n) gauge-invariant Lagrangian and the motion equation of the higher-dimensional topological defects are derived. Moreover, for closed defects, we study their important topological configuration, i.e., the higher-dimensional knotlike structures. Using the topological tensor currents and their preimages, we construct a series of metric independent integrals and prove their gauge independence. Similarmore » to the helicity integral characterizing one-dimensional knotlike vortex filament, these topological invariants are evaluated to the generalized linking numbers of higher-dimensional knotlike defects.« less
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  • The topologically nontrivial states of matter-charge and spin topological insulators, which exhibit, respectively, properties of the integer quantum Hall effect and the quantum spin Hall effect-are discussed. The topological characteristics (invariant with respect to weak adiabatic changes in the Hamiltonian parameters) which lead to such states are considered. The model of a 2D hexagonal lattice having symmetries broken with respect to time reversal and spatial inversion which was proposed by Haldane and marked the beginning of unprecedented activity in the study of topologically nontrivial states is discussed. This model relates the microscopic nature of the symmetry breaking with respect tomore » the time reversal to the occurrence of spontaneous orbital currents which circulate within a unit cell. Such currents become zero upon summation over the unit cell, but they may form spreading current states at the surface which are similar to the edge current states under the quantum Hall effect. The first model of spontaneous currents (exciton insulator model) is considered, and the possibility of implementing new topologically nontrivial states in this model is discussed.« less