State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China.
Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore.
Phys Rev Lett. 2023 Jan 6;130(1):016301. doi: 10.1103/PhysRevLett.130.016301.
Berry curvature dipole plays an important role in various nonlinear quantum phenomena. However, the maximum symmetry allowed for nonzero Berry curvature dipole in the transport plane is a single mirror line, which strongly limits its effects in materials. Here, via probing the nonlinear Hall effect, we demonstrate the generation of Berry curvature dipole by applied dc electric field in WTe_{2}, which is used to break the symmetry constraint. A linear dependence between the dipole moment of Berry curvature and the dc electric field is observed. The polarization direction of the Berry curvature is controlled by the relative orientation of the electric field and crystal axis, which can be further reversed by changing the polarity of the dc field. Our Letter provides a route to generate and control Berry curvature dipole in broad material systems and to facilitate the development of nonlinear quantum devices.
Berry 曲率偶极子在各种非线性量子现象中起着重要作用。然而,在输运平面中允许非零 Berry 曲率偶极子的最大对称性是单个镜面线,这强烈限制了其在材料中的效应。在这里,我们通过探测非线性 Hall 效应,证明了在 WTe_{2}中通过施加直流电场产生 Berry 曲率偶极子,这用于打破对称性约束。观察到 Berry 曲率的偶极矩与直流电场之间存在线性关系。Berry 曲率的极化方向由电场和晶体轴的相对取向控制,通过改变直流电场的极性可以进一步反转。我们的信件提供了在广泛的材料系统中产生和控制 Berry 曲率偶极子的途径,并有助于开发非线性量子器件。