First-principles method development for advanced quantum material simulations

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Date/Time:Monday, 28 Oct 2019 from 4:10 pm to 5:00 pm
Location:Phys 0005
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Dr. Yongxin Yao, Iowa State University

Abstract: Computational material discovery has reaped a remarkable success in the prediction of new electron-phonon superconductors and topological materials. The underlying backbone is the density functional theory (DFT), which has been reliable in predicting the total energy, electronic structure, electron-phonon coupling and other physical properties of weakly correlated materials. However, strong electron correlation effects often render the DFT calculations of limited accuracy or qualitatively wrong for materials containing transitional metal, rare-earth or actinide elements. This theoretical grand challenge has to be addressed in order to achieve the similar success in computational material discovery of correlated functional materials. In this talk, I will introduce the Gutzwiller density functional theory (GDFT) to simulate correlated quantum materials. It is represented by two levels of approaches: the DFT+Gutzwiller method and the correlation matrix renormalization method. The effectiveness of the GDFT is demonstrated by applications to transition metal, rare-earth and actinide single element systems and compounds. The access to the ground state Gutzwiller many-body wave function allows further advanced bonding and electronic structure analysis. The GDFT, upon some generalizations, further provides a natural theoretical framework, where noisy intermediate quantum computing technologies can be leveraged to achieve simulations of correlated electron systems, with accuracies systematically improvable.

Bio: Yongxin Yao received his B.S. in the department of intensive instruction in 2000 and M.S. in experimental condensed matter physics in 2003 from Nanjing University, China. He obtained Ph.D. in theoretical condensed matter physics from Iowa State University in 2009, under the supervision of Prof. Kai-Ming Ho. After graduation, he took a postdoc position in Ames Laboratory for the continuation of the research on Gutzwiller density functional theory for correlated electron systems. He was promoted to assistant scientist in 2011, associate scientist in 2015, and senior theoretical physicist this year. He is currently a leading PI in both the newly established quantum information science project in Ames Laboratory, and the computational materials science center hosted at Brookhaven National Laboratory. He is also a co-PI in the FWPs of exploratory theoretical method development and light-matter quantum control.