Universität zu Köln

Vinkler-Aviv, Yuval and Rosch, Achim ORCID: 0000-0002-6586-5721 (2018). Approximately Quantized Thermal Hall Effect of Chiral Liquids Coupled to Phonons. Phys. Rev. X, 8 (3). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2160-3308

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Abstract

The recent observation of a half-integer quantized thermal Hall effect in alpha-RuCl 3 is interpreted as a unique signature of a chiral spin liquid with a Majorana edge mode. A similar quantized thermal Hall effect is expected in chiral topological superconductors. The unavoidable presence of gapless acoustic phonons, however, implies that, in contrast to the quantized electrical conductivity, the thermal Hall conductivity kappa(xy) is never exactly quantized in real materials. Here, we investigate how phonons affect the quantization of the thermal conductivity, focusing on the edge theory. As an example, we consider a Kitaev spin liquid gapped by an external magnetic field coupled to acoustic phonons. The coupling to phonons destroys the ballistic thermal transport of the edge mode completely, as energy can leak into the bulk, thus drastically modifying the edge picture of the thermal Hall effect. Nevertheless, the thermal Hall conductivity remains approximately quantized, and we argue that the coupling to phonons to the edge mode is a necessary condition for the observation of the quantized thermal Hall effect. The strength of this edge coupling does, however, not affect the conductivity. We argue that for sufficiently clean systems the leading correction to the quantized thermal Hall effect,Delta kappa(xy)/T similar to sign(B) T-2, arises from an intrinsic anomalous Hall effect of the acoustic phonons due to Berry phases imprinted by the chiral (spin) liquid in the bulk. This correction depends on the sign but not the amplitude of the external magnetic field.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Vinkler-Aviv, Yuval UNSPECIFIED UNSPECIFIED UNSPECIFIED Rosch, Achim UNSPECIFIED orcid.org/0000-0002-6586-5721 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-178730
DOI:	10.1103/PhysRevX.8.031032
Journal or Publication Title:	Phys. Rev. X
Volume:	8
Number:	3
Date:	2018
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2160-3308
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute for Theoretical Physics
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language QUANTUM; TRANSPORT; STATES; HEAT Multiple languages Physics, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/17873