Time: 15:00 (UTC/GMT+8:00, Beijing/Shanghai), Apr. 28 (Wedn.), 2021

Venue: Rm. 401 KITS Meeting Room, KITS, 7# Building of UCAS [View Map]

Speaker: Prof. Gang Chen (HKU)

Abstract:

We study a novel type of non-Fermi liquid where there exist an infinite number of critical bosonic modes instead of finite bosonic modes for the conventional ones. We consider itinerant magnets with both conduction electrons and fluctuating magnetic moments in three dimensions. With Dzyaloshinskii-Moriya interaction, the moments fluctuate near a boson surface in the reciprocal space at low energies when the system approaches an ordering transition. The infinite number of critical modes on the boson surface strongly scatter the infinite gapless electrons on the Fermi surface and convert the metallic sector into a non-Fermi liquid. We explain the novel physical properties of this non-Fermi liquid. On the ordered side, a conventional non-Fermi liquid emerges due to the scattering by the gapless Goldstone mode from the spontaneous breaking of the global rotational symmetry. We discuss the general structure of the phase diagram in the vicinity of the quantum phase transition and clarify various crossover behaviors.

Reference: https://arxiv.org/abs/2102.09272

About the speaker:

Prof. Gang Chen received his bachelor's degree from USTC in 2004 and graduated with the University's highest honor. He received his PhD in 2010 from UC Santa Barbara, working with Prof. Leon Balents from the Kavli Institute for Theoretical Physics. He was appointed the professor position in 2015 at Fudan University, and elected into the 1000-youth-talent program. He was awarded the Daniel Tsui Fellowship from The University of Hong Kong in 2017, and Qiushi outstanding Youth scientist in 2018. He is currently working at University of Hong Kong. Prof. Chen has a broad interest in condensed matter theory, and most of his works are experimentally motivated.

Invited by Prof. Long Zhang