论文标题
表面状态对Weyl半含量非线性大厅效应的影响
Influence of the surface states on the nonlinear Hall effect in Weyl semimetals
论文作者
论文摘要
我们研究了表面态对非中心对称时间反转weyl半金属的非线性霍尔反应的影响。为此，我们使用最小的两波段模型在平板系统中对浆果曲率偶极子进行断层扫描。我们发现，在I型阶段，非线性霍尔响应对费米弧或其他微不足道的表面状态并不特别敏感。但是，在II型相中，我们发现这些表面状态对浆果曲率偶极子有很大贡献，从而导致非线性霍尔响应的厚度依赖性很强。此特征取决于表面状态的性质以及此后，从而取决于所采用的平板几何形状。为了评估这种情况对现实系统的有效性，我们通过对WTE $ _2 $的第一原理进行了浆果曲率偶极子计算，从而证实了表面状态对选定的平板几何形状的巨大影响。我们的结果表明，表面状态是否是拓扑，对非线性霍尔的反应比散装状态更有效。该预测不仅限于拓扑半学，因此应适用于拓扑琐碎的非中心对称材料和异质结构，为非线性霍尔效应的界面工程铺平了道路。
We investigate the influence of surface states on the nonlinear Hall response of non-centrosymmetric time-reversal invariant Weyl semimetals. To do so, we perform a tomography of the Berry curvature dipole in a slab system using a minimal two-band model. We find that in the type-I phase, the nonlinear Hall response is not particularly sensitive to the presence of Fermi arcs or other trivial surface states. However, in the type-II phase, we find that these surface states contribute substantially to the Berry curvature dipole, leading to a strong thickness dependence of the nonlinear Hall response. This feature depends on the nature of the surface states and, henceforth, on the slab geometry adopted. In order to assess the validity of this scenario for realistic systems, we performed Berry curvature dipole calculations by first principles on the WTe$_2$, confirming the dramatic impact of surface states for selected slab geometries. Our results suggest that surface states, being topological or not, can contribute much more efficiently to the nonlinear Hall response than bulk states. This prediction is not limited to topological semimetals and should apply to topologically trivial non-centrosymmetric materials and heterostructures, paving the way to interfacial engineering of the nonlinear Hall effect.
