Band theory of spatial dispersion in magnetoelectrics
Band theory of spatial dispersion in magnetoelectrics
复制标题
磁电空间色散能带理论
DOI：
--
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Ivo Souza
中科院分区：
文献类型：
--
作者：
A. Malashevich;Ivo Souza
本文在晶体动量表象下，计算了非中心对称绝缘晶体在光波矢一阶下的光学电导率。这个张量的时间偶部分描述自然的光学活动和时间奇部分描述非互易效应，如旋向性双折射。时间奇数部分可以被唯一地分解为类磁电和纯四极贡献。类磁电分量在静态极限中减少到冻结离子静态磁电极化率的无痕部分，而在有限的频率下，它获得了一些四极特性，以保持不变。通过比较有限和周期性样品的紧束缚计算，验证了在透明频率下轨道对电导率的贡献的表达式。
Working in the crystal-momentum representation, we calculate the optical conductivity of noncentrosymmetric insulating crystals at first order in the wave vector of light. The time-even part of this tensor describes natural optical activity and the time-odd part describes nonreciprocal effects such as gyrotropic birefringence. The time-odd part can be uniquely decomposed into magnetoelectriclike and purely quadrupolar contributions. The magnetoelectriclike component reduces in the static limit to the traceless part of the frozen-ion static magnetoelectric polarizability while at finite frequencies it acquires some quadrupolar character in order to remain translationally invariant. The expression for the orbital contribution to the conductivity at transparent frequencies is validated by comparing numerical tight-binding calculations for finite and periodic samples.