Thickness dependence of the anomalous Nernst effect and the Mott relation of Weyl semimetal Co2MnGa thin films

Gyu-Hyeon Park,Jonathan Noky,Dominik Kriegner,Andy Thomas,Kornelius Nielsch,Philipp Ritzinger,Peter Swekis,Yan Sun,Helena Reichlova,Sebastian T B Goennenwein,Jacob Gayles,Michaela Lammel,Richard Schlitz,Claudia Felser,Anastasios Markou

doi:10.1103/physrevb.101.060406

Abstract

We report a robust anomalous Nernst effect in Co2MnGa thin films in the thickness regime between 20 and 50 nm. The anomalous Nernst coefficient varied in the range of -2.0 to -3.0 uV/K at 300 K. We demonstrate that the anomalous Hall and Nernst coefficients exhibit similar behavior and fulfill the Mott relation. We simultaneously measure all four transport coefficients of the longitudinal resistivity, transversal resistivity, Seebeck coefficient, and anomalous Nernst coefficient. We connect the values of the measured and calculated Nernst conductivity by using the remaining three magneto-thermal transport coefficients, where the Mott relation is still valid. The intrinsic Berry curvature dominates the transport due to the relation between the longitudinal and transversal transport. Therefore, we conclude that the Mott relationship is applicable to describe the magneto-thermoelectric transport in Weyl semimetal Co2MnGa as a function of film thickness.

Highlights

Rapid CommunicationsGyu-Hyeon Park ,1,2 Helena Reichlova, Richard Schlitz, Michaela Lammel, Anastasios Markou, Peter Swekis, Philipp Ritzinger, Dominik Kriegner, Jonathan Noky, Jacob Gayles, Yan Sun, Claudia Felser, Kornelius Nielsch,
The anomalous Nernst effect (ANE) experimentally manifests as an anomalous transversal voltage, which is perpendicular to both the heat current and magnetization
We demonstrate that the anomalous Hall and Nernst coefficients exhibit similar behavior and fulfill the Mott relation

Summary

Rapid Communications

Gyu-Hyeon Park ,1,2 Helena Reichlova, Richard Schlitz, Michaela Lammel, Anastasios Markou, Peter Swekis, Philipp Ritzinger, Dominik Kriegner, Jonathan Noky, Jacob Gayles, Yan Sun, Claudia Felser, Kornelius Nielsch,. We report a robust anomalous Nernst effect in Co2MnGa thin films in the thickness regime between 20 and 50 nm. The anomalous Nernst coefficient varied in the range of −2.0 to −3.0 μV/K at 300 K. We demonstrate that the anomalous Hall and Nernst coefficients exhibit similar behavior and fulfill the Mott relation. We simultaneously measure all four transport coefficients of the longitudinal resistivity, transversal resistivity, Seebeck coefficient, and anomalous Nernst coefficient. We connect the values of the measured and calculated Nernst conductivity by using the remaining three magnetothermal transport coefficients, where the Mott relation is still valid. The intrinsic Berry curvature dominates the transport due to the relation between the longitudinal and transversal transport. We conclude that the Mott relationship is applicable to describe the magnetothermoelectric transport in Weyl semimetal Co2MnGa as a function of film thickness

INTRODUCTION

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Published by the American Physical Society

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SUMMARY