Max Planck Institute for the structure and dynamics of matter  

腾讯会议ID: 271-772-938

会议密码：0714

Abstract

Spontaneously broken symmetries are at the heart of many phenomena of quantum matter. However, determining the exact symmetries broken can be challenging due to experimental imperfections, such as misalignment of principle crystalline axis, irregularity of device geometry and non-uniform strain distribution. Focused-ion-beam is an ideal micro-fabrication tool with high precision which allows us to minimize these extrinsic imperfections, rendering the exploration of intrinsic electronic symmetries possible. The particular material under the spot light is the Kagome superconductor CsV3Sb5, where electronic correlations result in a cascade of charge ordered phases, leading to possible spontaneous symmetry breaking at the phase boundary.

Using FIB technique, we successfully fabricated hexagon-shaped devices with high precision. Great care was taken to align the structure with the in-plane lattice vectors (<0.5 deg) and to minimize shape deviations to avoid any symmetry lowering due to the structure’s shape itself. The directional in-plane electric transport unambiguously reveals that the in-plane C6 rotational symmetry remains intact down to cryogenic temperatures. Moreover, the spontaneous symmetry breaking occurs only when external perturbations, such as magnetic field and uniaxial strain, are included. Our results provide a unifying picture for the controversial charge order in Kagome metals and highlight the need for microscopic materials control in the identification of broken symmetries.

Reference : C. Guo et al., Nature 611, 461(2022); C. Guo et al., arXiv:2304.00972 (2023).

Brief CV of Dr. Chunyu Guo:

Chunyu Guo is currently a group leader researcher at Max Planck Institute for the structure and dynamics of matter (MPSD) at Hamburg, Germany. He received his PhD from Zhejiang University in 2019. Then he worked as a postdoc at EPFL, Switzerland. Since 2022, he worked as a group leader researcher in MPSD. He is interested in studying microstructured quantum matter using focused-ion-beam.

邀  请  人：董晓莉  研究员

联  系  人：傅琦（82649469）