189 citations · 378 across the 21 of their papers we have counts for
22 papers
Nonlinear optical responses of semiconducting graphene nanoribbons: Strong constraint from a hidden symmetry
Jiawei Ruan, Weichen Tang, Yang-Hao Chan +3
Nonlinear optical (NLO) responses are powerful tools for probing material structures, as they are highly sensitive to spatial symmetries. For instance, it is well known that having…
First-principles predictions of carrier mobility with record accuracy using GW perturbation theory
Nick Pant, Sabyasachi Tiwari, Steven G. Louie +2
Accurate prediction of carrier mobility is critical for the discovery and design of next-generation electronic materials. Despite sustained progress, state-of-the-art ab initio met…
Ab initio time-dependent GW approach for nonequilibrium exciton-phonon coupled dynamics across momentum space
Zhenfa Zheng, Benran Zhang, Jiawei Ruan +10
The dynamics of optical excitations in materials generally involves intertwined electron-hole (e-h) and electron-phonon (e-ph) interactions out of equilibrium. However, a full theo…
Photogeneration and signatures of coherent phonons in time-resolved photoemission spectroscopy: First-principles time-dependent adiabatic GW approach
Yang-hao Chan, Zhenglu Li, Steven G. Louie
Coherent lattice dynamics can be observed in pump-probe time-resolved and angle-resolved photoemission spectroscopy (TR-ARPES) as a periodic modulation of intensity and energy of p…
Moiré Phonons and Emergent Exciton-Phonon Coupling in a Moiré Heterobilayer
Can B. Uzundal, Woochang Kim, Zhiyuan Cui +13
Moiré superlattices have emerged as a new platform for engineering electronic and optical properties in van der Waals heterostructures, enabling control over correlated and exciton…
Tunable Interlayer Charge-transfer States in MoSe/WS Moiré Superlattices
Zheyu Lu, Jiahui Nie, Tianle Wang +15
Moiré superlattices formed by transition metal dichalcogenide (TMD) heterobilayers provide a versatile platform for studying strongly correlated electronic, excitonic, and topologi…
Advancing Quantum Many-Body GW Calculations on Exascale Supercomputing Platforms
Benran Zhang, Daniel Weinberg, Chih-En Hsu +9
Advanced ab initio materials simulations face growing challenges as increasing systems and phenomena complexity requires higher accuracy, driving up computational demands. Quantum…
Moiré excitons in generalized Wigner crystals
Jing-Yang You, Chih-En Hsu, Zien Zhu +8
Moiré superlattices of transition-metal dichalcogenide bilayers host strong Coulomb interactions residing in narrow electron bands, leading to correlated insulating states at fract…
Strong long-wavelength electron-phonon coupling in TaNi(Se,S)
Zhibo Kang, Burak Gurlek, Weichen Tang +9
The search for intrinsic excitonic insulators (EI) has long been confounded by coexisting electron-phonon coupling in bulk materials. Although the ground state of an EI may be diff…
Quantum Theory of Exciton Magnetic Moment: Interaction and Topological Effects
Gurjyot Sethi, Jiawei Ruan, Fang Zhang +4
Combining magnetometry with optical spectroscopy has uncovered novel quantum phenomena and is emerging as a powerful probe of quantum materials. However, the theory of the magnetic…
Non-excitonic mechanism for electronic and structural phase transitions in Ta2Ni(Se,S)5
Weichen Tang, Zhenglu Li, Cheng Chen +2
We present a first-principles study based on density functional theory (DFT) on the electronic and structural properties of Ta2NiSe5, a layered transition metal chalcogenide that h…
Ab initio study of exciton insulator phase: Emergent -wave spin textures from spontaneous excitonic condensation
Fang Zhang, Jiawei Ruan, Gurjyot Sethi +2
An excitonic insulator (EI) is a correlated many-body state of electron-hole pairs, potentially leading to high-temperature condensate and superfluidity. Despite ev…
Excitonic effects on infrared vibrational and Raman spectroscopy from first principles
Yang-Hao Chan, Zhenglu Li, Steven G. Louie
We develop a first-principles approach to compute infrared (IR) vibrational absorption and Raman scattering spectra with excitonic effects included. Our method is based on a pertur…
Exciton thermalization dynamics in monolayer MoS2: a first-principles Boltzmann equation study
Yang-hao Chan, Jonah B. Haber, Mit H. Naik +4
Understanding exciton thermalization is critical for optimizing optoelectronic and photocatalytic processes in many materials. However, it is hard to access the dynamics of such pr…
Phonon screening of excitons in atomically thin semiconductors
Woncheol Lee, Antonios M. Alvertis, Zhenglu Li +4
Atomically thin semiconductors, encompassing both 2D materials and quantum wells, exhibit a pronounced enhancement of excitonic effects due to geometric confinement. Consequently,…
Exciton-phonon coupling induces new pathway for ultrafast intralayer-to-interlayer exciton transition and interlayer charge transfer in WS2-MoS2 heterostructure: a first-principles study
Yang-hao Chan, Mit H. Naik, Jonah B. Haber +4
Despite the weak, van-der-Waals interlayer coupling, photoinduced charge transfer vertically across atomically thin interfaces can occur within surprisingly fast, sub-50fs timescal…
Phonon screening and dissociation of excitons at finite temperatures from first principles
Antonios M. Alvertis, Jonah B. Haber, Zhenglu Li +4
The properties of excitons, or correlated electron-hole pairs, are of paramount importance to optoelectronic applications of materials. A central component of exciton physics is th…
Exciton enhanced nonlinear optical responses in monolayer h-BN and MoS2: Insight from first-principles exciton-state coupling formalism and calculations
Jiawei Ruan, Y. -H. Chan, Steven G. Louie
Excitons are vital in the photophysics of materials, especially in low-dimensional systems. The conceptual and quantitative understanding of excitonic effects in nonlinear optical…
Coupling of Nonlocal Potentials to Electromagnetic Fields
Sohrab Ismail-Beigi, Eric K. Chang, Steven G. Louie
Nonlocal Hamiltonians are used widely in first-principles quantum calculations; the nonlocality stems from eliminating undesired degrees of freedom, e.g. core electrons. To date, a…
High Accuracy Many-Body Calculational Approaches for Excitations in Molecules
Jeffrey C. Grossman, Michael Rohlfing, Lubos Mitas +2
Two state-of-the-art computational approaches: quantum Monte Carlo (QMC), based on accurate total energies, and GW with exciton effects (GW-BSE), based on perturbation theory are e…
Variational quantum Monte Carlo study of two-dimensional Wigner crystals: exchange, correlation, and magnetic field effects
Xuejun Zhu, Steven G. Louie
The two-dimensional Wigner crystals are studied with the variational quantum Monte Carlo method. The close relationship between the ground-state wavefunction and the collective exc…
Freezing of the quantum Hall liquid at 1/7 and 1/9
Rodney Price, Xuejun Zhu, P. M. Platzman
We compare the free energy computed from the ground state energy and low-lying excitations of the 2-D Wigner solid and the fractional quantum Hall liquid, at magnetic filling facto…