Di Liberto M, Goldman N, Palumbo G
Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, CP 231, Campus Plaine, Brussels, B-1050, Belgium.
Nat Commun. 2020 Nov 23;11(1):5942. doi: 10.1038/s41467-020-19518-x.
Bloch oscillations (BOs) are a fundamental phenomenon by which a wave packet undergoes a periodic motion in a lattice when subjected to a force. Observed in a wide range of synthetic systems, BOs are intrinsically related to geometric and topological properties of the underlying band structure. This has established BOs as a prominent tool for the detection of Berry-phase effects, including those described by non-Abelian gauge fields. In this work, we unveil a unique topological effect that manifests in the BOs of higher-order topological insulators through the interplay of non-Abelian Berry curvature and quantized Wilson loops. It is characterized by an oscillating Hall drift synchronized with a topologically-protected inter-band beating and a multiplied Bloch period. We elucidate that the origin of this synchronization mechanism relies on the periodic quantum dynamics of Wannier centers. Our work paves the way to the experimental detection of non-Abelian topological properties through the measurement of Berry phases and center-of-mass displacements.
布洛赫振荡（BOs）是一种基本现象，在这种现象中，当受到一个力时，波包在晶格中会经历周期性运动。在广泛的合成系统中都观察到了布洛赫振荡，它与底层能带结构的几何和拓扑性质有着内在联系。这使得布洛赫振荡成为检测贝里相位效应（包括那些由非阿贝尔规范场描述的效应）的一个重要工具。在这项工作中，我们揭示了一种独特的拓扑效应，这种效应通过非阿贝尔贝里曲率和量子化威尔逊圈的相互作用，在高阶拓扑绝缘体的布洛赫振荡中表现出来。它的特征是与拓扑保护的带间拍频和倍增的布洛赫周期同步的振荡霍尔漂移。我们阐明，这种同步机制的起源依赖于万尼尔中心的周期性量子动力学。我们的工作为通过测量贝里相位和质心位移来实验检测非阿贝尔拓扑性质铺平了道路。
