Theory of orbital magnetic quadrupole moment and magnetoelectric susceptibility
Theory of orbital magnetic quadrupole moment and magnetoelectric susceptibility
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DOI：
10.1103/physrevb.98.020407
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发表时间：
2018-03
影响因子：
3.7
通讯作者：
A. Shitade;Hikaru Watanabe;Y. Yanase
中科院分区：
文献类型：
--
作者：
A. Shitade;Hikaru Watanabe;Y. Yanase
利用规范协变梯度展开，导出了周期系统中轨道磁四极矩的量子力学公式。该公式适用于零温和有限温下的绝缘体和金属。我们还证明了在零温度下的MQM和磁电（ME）的绝缘体的磁化率之间的直接关系。这表明MQM是ME效应的微观起源。利用这个公式，我们定量地估计了室温反铁磁半导体BaMn 2 As 2和CeMn 2 Ge 2 - x Si的这些量.我们发现，轨道的贡献ME磁化率是可比的，甚至占主导地位的自旋贡献。
We derive a quantum-mechanical formula of the orbital magnetic quadrupole moment (MQM) in periodic systems by using the gauge-covariant gradient expansion. This formula is valid for insulators and metals at zero and finite temperature. We also prove a direct relation between the MQM and magnetoelectric (ME) susceptibility for insulators at zero temperature. It indicates that the MQM is a microscopic origin of the ME effect. Using the formula, we quantitatively estimate these quantities for room-temperature antiferromagnetic semiconductors BaMn$_2$As$_2$ and CeMn$_2$Ge$_{2 - x}$Si$_x$. We find that the orbital contribution to the ME susceptibility is comparable with or even dominant over the spin contribution.