Brookhaven National Laboratory, New York, USA
报告摘要：Many correlated metallic materials are described by Landau Fermiliquid theory at low energies, but for Hund metals the Fermiliquid coherence scale TFL is found to be surprisingly small. In this Letter, we study the simplest impurity model relevant for Hund metals, the threechannel spinorbital Kondo model, using the numerical renormalization group (NRG) method and compute its global phase diagram. In this framework, TFL becomes arbitrarily small close to two new quantum critical points (QCPs) which we identify by tuning the spin or spinorbital Kondo couplings into the ferromagnetic regimes. We find quantum phase transitions to a singular Fermiliquid or a novel nonFermiliquid phase. The new nonFermiliquid phase shows frustrated behavior involving alternating overscreenings in spin and orbital sectors, with universal power laws in the spin (ω^−1/5), orbital (ω^1/5) and spinorbital (ω^1) dynamical susceptibilities. These power laws, and the NRG eigenlevel spectra, can be fully understood using conformal field theory arguments, which also clarify the nature of the nonFermiliquid phase.
报告人简介：Dr. Yilin Wang is a theoretical physicist, working in the field of computational condensed matter physics. His research interests include firstprinciple calculations of strongly correlated materials using density functional theory plus dynamical meanfield theory (DFT+DMFT) or plus Gutzwiller method (DFT+Gutzwiller), and also theoretically simulations of resonant inelastic xray scattering (RIXS) spectra based on exact diagonalization (ED) method. He also develops numerical codes such as iQIST package (https://github.com/iqist/iqist) implementing continuoustime quantum Monte Carlo (CTQMC) method and EDRIXS package (https://github.com/NSLSII/edrixs) for RIXS simulations. Recently, he focuses on studying the multiorbital metallic systems (Hund metals) where the correlations derive from the Hund’s couplings. He received his Ph.D in condensed matter physics from the Institute of Physics, Chinese Academy of Science in 2016. He is now working as a postdoc with Prof. Gabriel Kotliar in the center for computational materials, spectroscopy and design of Brookhaven National Laboratory, New York, USA. He was supported by the US Department of energy, Office of Science, Basic Energy Sciences as a part of the Computational Materials Science Program through the Center for Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy.
邀请人：王志俊
联系电话：82649070
