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Unconventional Transverse Transport above and below the Magnetic Transition Temperature in Weyl Semimetal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>EuCd</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>As</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Yang Xu, Lakshmi Kanta Das, Junzhang Ma, Changjiang Yi, Simin Nie, Yajun Shi, Apoorv Tiwari, Stepan S. Tsirkin, Titus Neupert, M. Medarde, M. Shi, J. Chang, Tian Shang

2021Physical Review Letters83 citationsDOIOpen Access PDF

Abstract

As exemplified by the growing interest in the quantum anomalous Hall effect, the research on topology as an organizing principle of quantum matter is greatly enriched from the interplay with magnetism. In this vein, we present a combined electrical and thermoelectrical transport study on the magnetic Weyl semimetal EuCd_{2}As_{2}. Unconventional contribution to the anomalous Hall and anomalous Nernst effects were observed both above and below the magnetic transition temperature of EuCd_{2}As_{2}, indicating the existence of significant Berry curvature. EuCd_{2}As_{2} represents a rare case in which this unconventional transverse transport emerges both above and below the magnetic transition temperature in the same material. The transport properties evolve with temperature and field in the antiferromagnetic phase in a different manner than in the paramagnetic phase, suggesting different mechanisms to their origin. Our results indicate EuCd_{2}As_{2} is a fertile playground for investigating the interplay between magnetism and topology, and potentially a plethora of topologically nontrivial phases rooted in this interplay.

Topics & Concepts

MagnetismWeyl semimetalAntiferromagnetismBerry connection and curvatureCondensed matter physicsPhysicsNernst effectHall effectParamagnetismPhase transitionSemimetalTopology (electrical circuits)Magnetic fieldNernst equationGeometric phaseQuantum mechanicsElectrodeMathematicsCombinatoricsBand gapTopological Materials and PhenomenaMagnetic properties of thin filmsGraphene research and applications