论文标题
时间逆转对称性和倾斜的作用在圆形光藻反应中
Role of time reversal symmetry and tilting in circular photogalvanic responses
论文作者
论文摘要
我们研究了考虑手性Weyl半准（WSM）的圆形光藻（CpG）反应中时间逆转对称性（TRS）的作用，而量化的CpG响应则通过倒置对称性对称（IS）和镜像对称性而保证了量化的CpG响应。 TRS断裂的WSM左一个和一个右手的Weyl节点（WNS），而TRS不变的WSM有两个左右手性WNS。我们表明，与基础WSM的拓扑电荷相比，这些特征可能会导致在较高值下对CpG响应的量化。浆果曲率和速度的行为是否保留或破坏TRS的事实进一步支持了这一事实。我们发现，TRS不变的II WSM的CpG响应以两倍和四倍的量子量化，而化学势分别是在与左和右鼠WN相关的能量附近选择的，而化学势分别选择了。相比之下，无论上述化学势上述选择，CpG响应中的量化都是由激活的WNS的拓扑电荷直接给出的。有趣的是，当与相反的手势相关的WNS的能量彼此接近时，我们注意到CpG响应中的非量化峰，因为此处考虑的TRS不变型I型WSM就是这种情况。此外，我们表明倾斜可以显着将CpG响应显着修改为倾斜方向上的速度变化，该速度通过费米分布函数进入CpG张量。鉴于这些令人兴奋的结果，第二阶CpG响应是一种有用的指标来表征所考虑的系统。此外，我们研究了CpG响应的动量解决结构，以与最终结果相关，并从晶格模型的角度加强我们的分析。
We study the role of time reversal symmetry (TRS) in the circular photogalvanic (CPG) responses considering chiral Weyl semimetal (WSM) while a quantized CPG response is guaranteed by broken of both inversion symmetry (IS) and mirror symmetries. The TRS broken WSM yields one left and one right chiral Weyl nodes (WNs) while there are two left and right chiral WNs for TRS invariant WSM. We show that these features can potentially cause the quantization of CPG response at higher values compared to the topological charge of the underlying WSM. This is further supported by the fact that Berry curvature and velocity behave differently whether the system preserves or breaks the TRS. We find the CPG responses for TRS invariant type-II WSM to be quantized at two and four times the topological charge of the activated WNs while the chemical potential are respectively chosen in the vicinity of energies associated with left and right chiral WNs. By contrast, irrespective of the above choice of the chemical potential, the quantization in CPG response is directly given by the topological charge of the activated WNs for TRS broken case. Interestingly, we notice non-quantized peak in CPG response when energies of WNs associated with opposite chiralities are close to each other as it is the case for TRS invariant type-I WSM considered here. Moreover, we show that the tilt can significantly modify the CPG response as velocity in the tilt direction changes which enters into the CPG tensor through the Fermi distribution function. Given these exciting outcomes, the second order CPG response emerges as a useful indicator to characterize the system under consideration. Furthermore, we investigate the momentum resolved structure of CPG response to relate with the final results and strengthen our analysis from the perspective of the lattice models.
