Long-range spin transport on the surface of topological Dirac semimetal
We theoretically propose the long-range spin transport mediated by the gapless surface states of a topological Dirac semimetal (TDSM). Low-dissipation spin current is a building block of next-generation spintronics devices. While conduction electrons in metals and spin waves in ferromagnetic insulat...
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Published in | Physical review research Vol. 3; no. 2; p. 023219 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
American Physical Society
01.06.2021
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Online Access | Get full text |
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Summary: | We theoretically propose the long-range spin transport mediated by the gapless surface states of a topological Dirac semimetal (TDSM). Low-dissipation spin current is a building block of next-generation spintronics devices. While conduction electrons in metals and spin waves in ferromagnetic insulators (FMIs) are the major carriers of spin current, their propagation length is inevitably limited due to Joule heating or Gilbert damping. In order to suppress dissipation and realize long-range spin transport, we here make use of the spin-helical surface states of TDSMs, such as Cd_{3}As_{2} and Na_{3}Bi, which are robust against disorder. Based on a junction of two FMIs connected by a TDSM, we demonstrate that the magnetization dynamics in one FMI induces a spin current on the TDSM surface flowing to the other FMI. By both the analytical transport theory on the surface and the numerical simulation of real-time evolution in the bulk, we find that the induced spin current takes a universal semiquantized value that is insensitive to the microscopic coupling structure between the FMI and the TDSM. We show that this surface spin current is robust against disorder over a long range, which indicates that the TDSM surface serves as a promising system for realizing spintronics devices. |
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ISSN: | 2643-1564 2643-1564 |
DOI: | 10.1103/PhysRevResearch.3.023219 |