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arXiv · 1806.10809

Edge magnetization and spin transport in an SU(2)-symmetric Kitaev spin liquid

V. S. de Carvalho·H. Freire·E. Miranda·R. G. Pereira
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Abstract

We investigate the edge magnetism and the spin transport properties of an SU(2)-symmetric Kitaev spin liquid (KSL) model put forward by Yao and Lee [Phys. Rev. Lett. \textbf{107}, 087205 (2011)] on the honeycomb lattice. In this model, the spin degrees of freedom fractionalize into a $\mathbb{Z}_{2}$ static gauge field and three species of either gapless (Dirac) or gapped (chiral) Majorana fermionic excitations. We find that, when a magnetic field is applied to a zigzag edge, the Dirac KSL exhibits a nonlocal magnetization associated with the existence of zero-energy edge modes. The application of a spin bias $V=μ_{\uparrow}-μ_{\downarrow}$ at the interface of the spin system with a normal metal produces a spin current into the KSL, which depends, in the zero-temperature limit, as a power-law on $V$ for both Dirac and chiral KSLs, but with different exponents. Lastly, we study the longitudinal spin Seebeck effect, in which a spin current is driven by the combined action of a magnetic field perpendicular to the plane of the honeycomb lattice and a thermal gradient at the interface of the KSL with a metal. Our results suggest that edge magnetization and spin transport can be used to probe the existence of charge-neutral edge states in quantum spin liquids.

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V. S. de Carvalho, H. Freire, E. Miranda, R. G. Pereira. 2018-06-28. Edge magnetization and spin transport in an SU(2)-symmetric Kitaev spin liquid. https://doi.org/10.1103/physrevb.98.155105

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