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Yu Yang Fredrik Liu
My research interests lie primarily in accurate force predictions. I spent the first two years of my undergraduate studies doing experiments, before moving to first-principle calculations in the hope to predict the large scale behaviour from the simple small scale laws. Although the mean-field theory used in density functional theory (DFT) is exact in principle, the exchange-correlation energy functional has to be approximated and is not universally accurate. Now I am turning to the full many-electron Schrödinger equation which is believed to be capable of predicting and describing almost everything in everyday life. The leading approach to solve this equation is by Quantum Monte Carlo (QMC) and it could give very accurate ground state calculations.
We will exploit techniques that allow interatomic forces and force constants to be calculated within QMC. This will be used to perform accurate studies of the consequences of atomic motion in real-life materials. The case studies include van der Waals interaction, bond breaking in experimentally relevant systems, and phonons in high temperature superconductors. This should not only provide physical insights but also open new avenues in material design.
Direct evaluation of the Force Constant Matrix in Quantum Monte Carlo
J. Chem. Phys. 150, 034104 (2019) Editor's Pick
Direct calculation of the linear thermal expansion coefficients of MoS2 via symmetry-preserving deformations
Phys. Rev. B 94, 134303 (2016)
Weak Van der Waals Stacking, Wide-Range Band Gap, and Raman Study on Ultrathin Layers of Metal Phosphorus Trichalcogenides
ACS Nano 10(2), 1738-1743 (2016)
Vibrational frequencies with Quantum Monte Carlo, Frontiers in Condensed Matter Physics, 9-10 Jan 2017; CCP9 Computational Electronic Structure of Condensed Matter (Runner-up Best Poster Award), 10-11 Apr 2017.
Calculating the force constant matrix via quantum Monte Carlo, APS March Meeting, Los Angeles. 5 Mar 2018.
A quantum Monte Carlo approach to van der Waals interaction, APS March Meeting, Los Angeles. 8 Mar 2018.