Asymmetric modulation of Majorana excitation spectra and nonreciprocal thermal transport in the Kitaev spin liquid under a staggered magnetic field
Asymmetric modulation of Majorana excitation spectra and nonreciprocal thermal transport in the Kitaev spin liquid under a staggered magnetic field
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交错磁场下基塔耶夫自旋液体中马约拉纳激发光谱和不可逆热传输的不对称调制
DOI：
10.1103/physrevb.105.165152
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发表时间：
2022
影响因子：
3.7
通讯作者：
and Yukitoshi Motome
中科院分区：
文献类型：
--
作者：
Kazuki Nakazawa;Yasuyuki Kato;and Yukitoshi Motome
我们提出的Majorana带结构和热输运性质的Kitaev蜂窝模型下的交错磁场，除了一个均匀的理论结果。马约拉纳能带结构在动量空间中是不对称调制的，并且谷自由度由均匀和交错磁场的大小和方向激活和控制;因此，马约拉纳激发是有间隙的或无间隙的，后者通常具有马约拉纳费米表面，与没有磁场的点节点相反。我们表明，不对称变形的马约拉纳带导致非互易的热输运。线性热导率的场依赖性与Majorana间隙的大小相关，而非线性热导率的场依赖性与Majorana激发谱的不对称性相关。我们显示的热电流的估计和讨论的线性响应是实验测量的，而未来的改进是需要观察的非线性的。我们还讨论了如何调制的热电流的磁场和传统的磁振子，其中后者预计在异质结实现内部交错磁场的贡献的其他额外的影响。
We present the theoretical results for the Majorana band structure and thermal transport properties in the Kitaev honeycomb model under a staggered magnetic field in addition to a uniform one. The Majorana band structure is asymmetrically modulated in momentum space, and the valley degree of freedom is activated and controlled by the magnitudes and directions of the uniform and staggered magnetic fields; as a result, the Majorana excitation is either gapped or gapless, the latter of which in general has Majorana Fermi surfaces, in contrast to the point nodes in the absence of the fields. We show that the asymmetric deformation of the Majorana band leads to a nonreciprocal thermal transport. The field dependence of the linear thermal conductivity is correlated with the magnitude of the Majorana gap, while that of the nonlinear thermal conductivity is associated with the asymmetry of the Majorana excitation spectra. We show the estimates of the thermal currents and discuss that the linear response is experimentally measurable, whereas future improvement is required for the observation of the nonlinear one. We also discuss how the thermal currents are modulated by other additional effects of the magnetic field and contributions from conventional magnons, the latter of which are expected in heterostructures to realize an internal staggered magnetic field.