Theory of the Spin Seebeck Effect at a Topological-Insulator/Ferromagnetic-Insulator Interface

Autor:	Okuma, Nobuyuki, Masir, Massoud Ramezani, MacDonald, Allan H.
Rok vydání:	2016
Předmět:	Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter - Materials Science Condensed Matter - Strongly Correlated Electrons
Zdroj:	Phys. Rev. B 95, 165418 (2017)
Druh dokumentu:	Working Paper
DOI:	10.1103/PhysRevB.95.165418
Popis:	The spin-Seebeck effect refers to voltage signals induced in metals by thermally driven spin currents in adjacent magnetic systems. We present a theory of the spin-Seebeck signal in the case where the conductor that supports the voltage signal is the topologically protected two-dimensional surface-state system at the interface between a ferromagnetic insulator (FI) and a topological insulator (TI). Our theory uses a Dirac model for the TI surface-states and assumes Heisenberg exchange coupling between the TI quasiparticles and the FI magnetization. The spin-Seebeck voltage is induced by the TI surface states scattering off the nonequilibrium magnon population at the surface of the semi-infinite thermally driven FI. Our theory is readily generalized to spin-Seebeck voltages in any two-dimensional conductor that is exchange-coupled to the surface of a FI. Surface-state carrier-density-dependent signal strengths calculated using Bi$_2$Te$_3$ and yttrium iron garnet material parameters are consistent with recent experiments. Comment: 10 pages, 7 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1612.04916 Zobrazit plný text záznamu View this record from Arxiv