论文标题
磁场诱导的拓扑转换和广泛的基塔维模型中的热导率
Magnetic-field Induced Topological Transitions and Thermal Conductivity in a Generalized Kitaev Model
论文作者
论文摘要
关于基塔夫自旋液体候选材料的最新实验报告了导热性的非单调行为与磁场的函数，这导致对其起源的解释相互矛盾。在这种发展的驱动下，我们研究了广义基塔伊夫模型的热导率的磁场依赖性，该模型允许不同通量扇区之间的相变为磁场的函数。随着磁场的增加，由于Majorana fermions引起的热导率显示出倾角结构，这是由Kitaev旋转液体不同通量部门之间的过渡引起的，或者是改变了同一通量扇形内的主要Chern数量的拓扑转变。结果表明，Chern数的变化与磁场引起的四毛毛菌相互作用密切相关。热导率中的非单调行为在有限温度下出现，当温度降低到零时，它会变得较弱。我们的模型为Kitaev旋转液体提供了一种通用机制，以开发导热性的非单调磁场依赖性，而与逼真的材料的详细比较仍然是未来研究的一个开放问题。
Recent experiments on Kitaev spin liquid candidate materials reported non-monotonic behavior of thermal conductivity as a function of magnetic field, which lead to conflicting interpretations of its origin. Motivated by this development, we study the magnetic field dependence of thermal conductivity of a generalized Kitaev model, which allows the phase transitions between different flux sectors as a function of the magnetic field. The thermal conductivity due to Majorana fermions shows dip-bump structures as the magnetic field increases, which is caused by either the transitions between different flux sectors of Kitaev spin liquids or the topological transitions that change the Majorana Chern number within the same flux sector. It is shown that the change of Chern number is closely related to the four-Majorana-fermion interaction induced by the magnetic field. The non-monotonic behavior in thermal conductivity emerges at finite temperature, and it becomes weaker when temperature decreases towards zero. Our model provides a generic mechanism for the Kitaev spin liquids to develop non-monotonic magnetic-field dependence of thermal conductivity while the detailed comparison to realistic materials remains an open question for future investigation.
