Abstract
Weyl semimetals (WSMs) are intriguing topological states of matter that support various anomalous magnetotransport phenomena. One such phenomenon is a positive longitudinal magnetoconductivity and the associated planar Hall effect, which arise due to an effect known as chiral anomaly which is nonzero in the presence of electric and magnetic fields , and . In this paper we show that another fascinating effect is the planar thermal Hall effect (PTHE), associated with positive longitudinal magnetothermal conductivity (LMTC), which arise even in the absence of chiral anomaly . This effect is a result of chiral magnetic effect (CME) and involves the appearance of an in-plane transverse temperature gradient when the current due to a nonzero temperature gradient and the magnetic field are not aligned with each other. Using semiclassical Boltzmann transport formalism in the relaxation time approximation we compute both longitudinal magnetothermal conductivity and planar thermal Hall conductivity (PTHC) for a time-reversal symmetry-breaking WSM. We find that both LMTC and PTHC are quadratic in in type-I WSM whereas each follows a linear- dependence in type-II WSMs in a configuration where and B are applied along the tilt direction. In addition, we investigate the Wiedemann-Franz law for an inversion symmetry-broken WSM (e.g., and find that this law is violated in these systems due to both chiral anomaly and CME.
- Received 21 January 2019
DOI:https://doi.org/10.1103/PhysRevB.100.115139
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