Interplay of Dirac electrons and magnetism in AMnBi2 (A=Ca, Sr)

Anmin Zhang; Changle Liu; Changjiang Yi; Guihua Zhao; Tian-long Xia; Jianting Ji; Youguo Shi; Rong Yu; Xiaoqun Wang; Changfeng Chen; Qingming Zhang

doi:10.1038/ncomms13833

arXiv · 1703.02712

Interplay of Dirac electrons and magnetism in AMnBi2 (A=Ca, Sr)

Anmin Zhang·Changle Liu·Changjiang Yi·Guihua Zhao·Tian-long Xia·Jianting Ji·Youguo Shi·Rong Yu·Xiaoqun Wang·Changfeng Chen·Qingming Zhang

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Abstract

Dirac materials exhibit intriguing low-energy carrier dynamics that offer a fertile ground for novel physics discovery. Of particular interest is the interplay of Dirac carriers with other quantum phenomena, such as magnetism. Here we report on a two-magnon Raman scattering study of AMnBi2 (A=Ca, Sr), a prototypical magnetic Dirac system comprising alternating Dirac-carrier and magnetic layers. We present the first accurate determination of the exchange energies in these compounds and, by comparison to the reference compound BaMn2Bi2, we show that the Dirac-carrier layers in AMnBi2 significantly enhance the exchange coupling between the magnetic layers, which in turn drives a charge-gap opening along the Dirac locus. Our findings break new grounds in unveiling the fundamental physics of magnetic Dirac materials, which offer a novel platform for probing a distinct type of spin-Fermion interaction. The outstanding properties of these materials allow a delicate manipulation of the interaction between the Dirac carriers and magnetic moments, thus holding great promise for applications in magnetic Dirac devices.

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Anmin Zhang, Changle Liu, Changjiang Yi, Guihua Zhao, Tian-long Xia, Jianting Ji, Youguo Shi, Rong Yu, Xiaoqun Wang, Changfeng Chen, Qingming Zhang. 2017-03-08. Interplay of Dirac electrons and magnetism in AMnBi2 (A=Ca, Sr). https://doi.org/10.1038/ncomms13833

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