Berry phase mechanism for optical gyrotropy in stripe-ordered cuprates
Berry phase mechanism for optical gyrotropy in stripe-ordered cuprates
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DOI：
10.1103/physrevb.87.165110
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发表时间：
2013-04-05
影响因子：
3.7
通讯作者：
Moore, Joel E.
中科院分区：
文献类型：
--
作者：
Orenstein, J.;Moore, Joel E.
光学回旋性，即左右圆偏振光简并度的提升，可以通过时间反演或手征对称性破缺产生。在高温超导体La 2-xCuO 4（LBCO）中，旋向性在与电荷条纹顺序相同的温度下开始，这表明条纹方向从一个平面到下一个平面的旋转产生破坏手征对称性的螺旋图案。为了进一步检验这一手征叠加假说，有必要了解手征性产生回转性的物理机制。在本文中，我们表明，在手征金属，光学陀螺是一个后果的Berry曲率在动量空间。我们描述了一个物理图象，表明手征金属中的旋向性与巡游铁磁体中的反常霍尔效应密切相关。然后，我们计算了一个给定的Berry曲率的回旋响应的大小使用的半经典图片的反常速度和玻尔兹曼输运理论。为了将这一物理图像与实验联系起来，我们计算了两个紧束缚模型中的Berry曲率。第一个模型的动机是由LBCO的结构，并说明如何创建时，条纹扰动被添加到一个简单的立方模型的陀螺。在第二个模型中，我们研究了显着增强的回旋系数时，Rashba自旋轨道耦合。根据这些模型计算了预期的反射偏振旋转的大小，并与实验数据进行了比较。DOI：10.1103/PhysRevB.87.165110
Optical gyrotropy, the lifting of degeneracy between left and right circularly polarized light, can be generated by either time-reversal or chiral symmetry breaking. In the high-T-c superconductor La2-xBaxCuO4 (LBCO), gyrotropy onsets at the same temperature as charge stripe order, suggesting that the rotation of the stripe direction from one plane to the next generates a helical pattern that breaks chiral symmetry. In order to further test this chiral stacking hypothesis it is necessary to develop an understanding of the physical mechanisms by which chirality generates gyrotropy. In this paper we show that, in chiral metals, optical gyrotropy is a consequence of Berry curvature in momentum space. We describe a physical picture showing that gyrotropy in chiral metals is closely related to the anomalous Hall effect in itinerant ferromagnets. We then calculate the magnitude of the gyrotropic response for a given Berry curvature using the semiclassical picture of anomalous velocity and Boltzmann transport theory. To connect this physical picture with experiment, we calculate the Berry curvature in two tight-binding models. The first model is motivated by the structure of LBCO and illustrates how gyrotropy is created when stripe perturbations are added to a simple cubic model. In the second model, we examine the dramatic enhancement of the gyrotropic coefficient when Rashba spin-orbit coupling is introduced. The magnitude of the rotation of polarization on reflection expected based on these models is calculated and compared with experimental data. DOI: 10.1103/PhysRevB.87.165110