AI 中文总结
该研究理论探究霍普夫链接半金属的量子几何性质，利用其PT对称性抑制贝里曲率贡献，通过微扰实现仅由量子度量驱动的内禀非线性霍尔效应，可区分链接相与平凡相。
AI 中文摘要
量子几何包含量子度量和贝里曲率，在固体的电子输运性质中发挥重要作用。本研究从理论上探究霍普夫链接半金属的量子几何性质，该半金属是具有节点链接-非链接转变特征的独特拓扑类别。我们计算了霍普夫链接的带间光导率，其可有效区分链接相与平凡相。近期研究证实量子度量偶极子介导无散射非线性霍尔效应，在贝里曲率偶极子对非线性霍尔电导率的贡献消失的系统中，该效应更具研究价值。由于霍普夫链接半金属具有内在PT对称性，其贝里曲率及对应的非线性霍尔效应贡献被完全抑制。因此，通过引入合适的微扰，霍普夫半金属中仅因量子度量会产生有限的非线性霍尔电导率。值得注意的是，这种完全内禀、由对称性驱动的非线性响应完全不与外禀成分混合。
英文摘要
Quantum geometry, comprising of quantum metric and Berry curvature, plays a significant role in the electronic transport properties of solids. In this work, we theoretically investigate the quantum geometric properties of a Hopf-link semimetal, a distinct topological class that is charecterized by a nodal link-unlink transition. We compute the interband optical conductivity of the Hopf link, which effectively distinguishes between linked and trivial phases. While recent studies establish quantum metric dipole-mediated scattering-free nonlinear Hall effect, this effect becomes even more fascinating in systems where the Berry-curvature-dipole contribution to nonlinear Hall conductivity vanishes. Owing to the underlying $PT$ symmetry of the Hopf-link semimetal, the Berry curvature and its corresponding contribution to the nonlinear Hall effect are entirely suppressed. Consequently, by introducing an appropriate perturbation, a finite nonlinear Hall conductivity emerges solely due to the quantum metric in the Hopf semimetal. Notably, this purely intrinsic, symmetry-driven nonlinear response remains entirely unmixed with extrinsic components.
Comments6 Pages, 5 PDF Figures (main text) and 3 Pages, 2 PDF FIgures (Supplementary Materials). Comments are welcome
