IAS Center for Quantum Technologies Seminar Series

Unconventional Charge Density Wave in Kagome Superconductor AV3Sb5 (A=K, Cs, Rb)


The intricate interplay between novel lattice geometry and spontaneous symmetry-breaking states is at the forefront of contemporary research on quantum materials. Charge density waves (CDWs), a translational symmetry-breaking electronic fluid state of matter, are in the spotlight to unravel intertwined quantum materials. This includes cuprate high-TC superconductors as well as Moiré superlattices and, most recently, kagome metals AV3Sb5 (A=K, Rb, Cs) where the CDW emerges as a leading electronic instability near van Hove filling. The formation of this CDW state breaks the time-reversal symmetry and is possibly responsible for the novel superconductivity with roton pair density wave and electronic nematicity, which brings out a new showcase for intertwined orders. In this talk, the speaker will present his experimental work on the CDW state in AV3Sb5 combining results from angle-resolved photoemission spectroscopy (ARPES) and X-ray scatterings. His work demonstrates a rare realization of two conjoined CDWs with the absence of acoustic phonon anomalies that firmly excludes the conventional CDW scenario. The conjoined CDWs he observed transcend the phenomenology that could be derived from a sole kagome sublattice and is linked to the novel superconducting phase, which provide critical information to understand the enlarged complexity of intertwined symmetry-breaking orders.


About the speaker

Dr. LI Haoxiang is currently a postdoctoral researcher at the Oak Ridge National Laboratory in the United States. He received his PhD from the University of Colorado Boulder. His research work focuses on probing quantum many-body states that emerge from charge, spin, and lattice interactions using angle-resolved photoemission spectroscopy and various X-ray scattering techniques. His current research interest focuses on novel strongly correlated states, such as topological flat band state in frustrated lattice systems, spin-lattice interactions in quantum spin liquid materials and the intertwine orders in novel kagome lattice systems.


For Attendees' Attention:

This talk will be held online via Zoom. To join the talk online, please join the Zoom meeting at https://hkust.zoom.us/j/98444086380 (meeting ID: 984 4408 6380 / Passcode: 683593).


About the center

For more information, please refer to the center website at https://iascqt.hkust.edu.hk/.

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