论文标题
Weyl半法中异常引起的声音吸收
Anomaly-induced sound absorption in Weyl semimetals
论文作者
论文摘要
我们在磁场中的Weyl半学中发展了一种半经典理论。我们专注于对吸收的贡献，该吸收是由于手性异常和手性磁效应而导致的，或等效地造成的浆果单孔。声音吸收显示主要来自能量空间中的Weyl节点的运动，与声波的传播有关。我们认为，当相反的传播方向的吸收与磁场的相反方向相反时，发生声学磁性二色性，这可能是对带拓扑的确切探针。即使在磁场中，与单极相关的声磁磁磁强；与正异常相关的传输磁性相比，该作用符号的差异源于在声音传播问题中存在山谷电化学失衡而没有磁场的情况。在少量Weyl节点的中心对称Weyl半法中，在低频率下的磁吸附为负，但可以随频率越来越多地改变符号。
We develop a semiclassical theory of sound absorption in Weyl semimetals in magnetic fields. We focus on the contribution to the absorption that stems from the existence of Berry monopoles in the band structure of such materials, or, equivalently, due to the chiral anomaly and chiral magnetic effect. Sound absorption is shown to come primarily from the motion of Weyl nodes in energy space, associated with the propagation of a sound wave. We argue that acoustic magneto-chiral dichroism, which occurs when absorption of sound is different for opposite propagation directions, and for opposite directions of the magnetic field, can be a definitive probe of band topology. The part of the monopole-related sound magnetoabsorption that is even in the magnetic field is negative in time-reversal Weyl materials. The difference in the sign of the effect as compared to the positive anomaly-related transport magnetoconductance stems from the existence of valley electrochemical imbalances without magnetic field in the sound propagation problem. In centrosymmetric Weyl semimetals with few Weyl nodes, the magneto-absorption is negative at low frequencies, but can change sign with increasing frequency.
