# Thermopower and thermal conductivity in the Weyl semimetal NbP

## TL;DR

This study investigates thermopower and thermal conductivity in NbP, revealing giant magnetothermopower effects and quantum oscillations linked to high charge-carrier mobility in this Weyl semimetal.

## Contribution

It provides the first detailed temperature- and field-dependent thermopower and thermal conductivity measurements on NbP, highlighting large magnetothermopower effects and quantum oscillations.

## Key findings

- Giant adiabatic magnetothermopower of 800 μV/K at 50 K in 9 T
- Pronounced quantum oscillations in thermal conductivity and thermopower
- Correlation of observed effects with high charge-carrier mobility

## Abstract

The Weyl semimetal NbP exhibits an extremely large magnetoresistance (MR) and an ultra-high mobility. The large MR originates from a combination of the nearly perfect compensation between electron- and hole-type charge carriers and the high mobility, which is relevant to the topological band structure. In this work we report on temperature- and field-dependent thermopower and thermal conductivity experiments on NbP. Additionally, we carried out complementary heat capacity, magnetization, and electrical resistivity measurements. We found a giant adiabatic magnetothermopower with a maximum of 800 $\mu$V/K at 50 K in a field of 9 T. Such large effects have been observed rarely in bulk materials. We suggest that the origin of this effect might be related to the high charge-carrier mobility. We further observe pronounced quantum oscillations in both thermal conductivity and thermopower. The obtained frequencies compare well with our heat capacity and magnetization data.