Research
Quantum dynamics simulation
Background
We are interested in developing real-time simulation method to study nonequilibrium quantum dynamics. In particular we are working on Green's function formalism, DMRG, and density matrix methods. The application include emerging phenomena in strongly driven systems, nonlinear optical responses, time-resolved and pump-probe spectroscopy.
Giant exciton-enhanced shift currents and direct current conduction with subbandgap photo excitations produced by many-electron interactions, Yang-Hao Chan, Diana Y Qiu, Felipe H da Jornada, Steven G Louie, PNAS 118, e1906938118 (2021)
Using dynamic mode decomposition to predict the dynamics of a two-time non-equilibrium Green's function, Jia Yin, Yang-hao Chan, Felipe da Jornada, Diana Qiu, Steven G Louie, Chao Yang, arXiv:2203.14892
Our recent efforts focus on excitonic effects on nonlinear optical response. Based on a sum-over-state approach we computed shift current, second harmonic, and high harmonic generation spectrum for monolayer MoS2, h-BN, and BN nanotubes. We further derive an expression for second order optical response from the diagrammatic approach, which could be extended to higher orders.
Excitonic effects in nonlinear optical responses: Exciton-state formalism and first-principles calculations, Jiawei Ruan, Y-H Chan, Steven G Louie, arXiv:2310.09674
Large shift currents via in-gap and charge-neutral excitons in a monolayer and nanotubes of BN,Yi-Shiuan Huang, Yang-Hao Chan, Guang-Yu Guo, Phys. Rev. B 108, 075413 (2023)
Diagrammatic approach to excitonic effects on nonlinear optical response, Yu-Tzu Chang, Yang-Hao Chan, Phys. Rev. B 109, 155437 (2024)
Resources
Many-body physics in spectroscopy and quantum phases
Background
Quasi-particle properties beyond ground state calculations are important in condensed matter physics. We aim to unravel quasi-particle features in spectroscopy with first-principle diagrammatic based methods. We are also fascinated by the exotic quantum phases in strongly correlated systems. We are interested in developing numerical methods to understand their properties.
Exciton-Driven Renormalization of Quasiparticle Band Structure in Monolayer MoS2, Yi Lin, Yang-hao Chan, Woojoo Lee, Li-Syuan Lu, Zhenglu Li, Wen-Hao Chang, Chih-Kang Shih, Robert A Kaindl, Steven G Louie, Alessandra Lanzara, arXiv: 2205.05821
Polaron spectral properties in doped ZnO and from first principles, Gabriel Antonius, Yang-Hao Chan, Steven G Louie, Phys. Rev. Research, 2, 043296 (2020)
Predominance of non-adiabatic effects in zero-point renormalization of the electronic band gap, Anna Miglio, Véronique Brousseau-Couture, Emile Godbout, Gabriel Antonius, Yang-Hao Chan, Steven G Louie, Michel Côté, Matteo Giantomassi, Xavier Gonze, npj Computational Materials 6, 1 (2020)
Exciton features are recently reported in time-resolved angle-resolved photoemission spectroscopy. We proposed to understand this feature in terms of the “self-driven exciton-Floquet effect,” and show that materials’ electronic structure can also be engineered in this way. We demonstrate such effects in monolayer MoS2 from first-principles calculations.
Giant self-driven exciton-Floquet signatures in time-resolved photoemission spectroscopy of MoS from time-dependent GW approach, Y-H Chan, Diana Y Qiu, Felipe H da Jornada, Steven G Louie, PNAS 120 (32) e2301957120 (2023)
Driving non-trivial quantum phases in conventional semiconductors with intense excitonic fields, Vivek Pareek, David R Bacon, Xing Zhu, Yang-Hao Chan, Fabio Bussolotti, Nicholas S Chan, Joel Pérez Urquizo, Kenji Watanabe, Takashi Taniguchi, Michael KL Man, Julien Madéo, Diana Y Qiu, Kuan Eng Johnson Goh, Felipe H da Jornada, Keshav M Dani, arXiv:2403.08725
Electronic structure study
Background
We apply first-principle method to study materials properties. We explores driving mechanism of a variety of charge density waves in TMDs and their signatures in the experiment. We are also interested in topological materials and their optical properties.
Charge density wave transition in single-layer titanium diselenide, Peng Chen, Y-H Chan, X-Y Fang, Yi Zhang, Mei-Yin Chou, S-K Mo, Zahid Hussain, A-V Fedorov, T-C Chiang, Nature communications 6, 1 (2015)