Research

Ultrafast dynamics in Unconventional Magnets

Unconventional magnetic phases, particularly altermagnets, have attracted rapidly growing interest due to their momentum-dependent spin splitting and nodal spin textures despite a fully compensated magnetization. Their unique symmetry and electronic structure suggest fundamentally new nonequilibrium responses under ultrafast light excitation, a regime that remains largely unexplored. We are broadly interested in the emergent ultrafast phenomena arising from the interplay of spin, charge, and lattice degrees of freedom in these materials, and in how light can be used to probe and control such dynamics.

Zhou, Z., Sharma, S. Dewhurst, J.K., and He, J., Magnetizing altermagnets by ultrafast asymmetric spin dynamics. arXiv preprint arXiv:2502.01258. (2025)

Zhou, Z., Sharma, S., He, J., Zhou, Z., Sharma, S., He, J., Ultrafast all-optical control of magnetization in g-wave altermagnet CrSb. Physical Review B, 113, 064434, 2026.

Zhou, Z. and He, J., Ultrafast Spin Dynamics beyond s-Wave Magnets: A Universal Polarization Dependence. Nano Letters, 25(44),15978-15984 (2025).

Electronic/Magnetic properties of Quantum materials

We investigate electronic structure, magnetism, and related quantum properties of materials, including spin and valley physics, topological states. In addition, we study functional properties relevant to energy and spintronics, such as photocatalysis, thermoelectric and thermal transport, optoelectronic responses, and energy storage applications. Our goal is to reveal, control, and engineer emergent quantum phase and multifunctional properties in complex materials. See related paper:

Nanoscale 9 (6), 2246-2252, (2017). (Citation>150); Nanoscale, 2023,15, 16992-16997; J. Mater. Chem. C, 2021, 9, 11132-11141; J. Mater. Chem. C, 2016, 4, 2518-2526. (citation >250); J. Mater. Chem. C, 2016, 4, 11143-11149; (citation >200) J. Mater. Chem. C, 2016, 4, 6500-6509. (citation >160); Nanoscale, 2019, 11, 356-364. (citation >140);

Photoinduced Carrier Dynamics in Energy Materials

Carrier relaxation and energy dissipation following photoexcitation govern ultrafast processes in energy materials such as photocatalysts and solar cells. Using time-dependent density functional theory (TDDFT) and ab initio non-adiabatic molecular dynamics, we investigate non-equilibrium carrier, spin, and energy relaxation dynamics across a range of systems, including photovoltaic and catalytic materials, two-dimensional materials, and heterostructures.

Nano Lett., 2023, 23, 8348-8354.; J. Am. Chem. Soc., 2022, 144, 18126-18134.; J. Am. Chem. Soc., 2024, 146, 29905-29912; Nano Lett., 2023, 23, 5688–5695; J. Phys. Chem. Lett.,13, 4955-4962 (2022)

Laser-Matter Interaction on Ultrafast Timescale

When quantum materials are driven far from equilibrium by intense laser excitation, their properties can be dramatically modified. A variety of intriguing non-equilibrium phenomena can emerge, including charge transfer, ultrafast demagnetization, structural phase transitions, polarization switching, and even light-induced superconductivity. We aim to uncover, control, and ultimately engineer non-equilibrium physical and chemical properties in materials using tailored laser pulses, by exploiting the coupled dynamics of spin, charge, and lattice degrees of freedom.

Nano Lett. 24, 12062-12069 (2024); J. Phys. Chem. Lett., 11, 6219-6226 (2020); Nano Lett. 2021, 21, 3237−3244; J. Phys. Chem. Lett. 2022, 13, 2765−2771; J. Phys. Chem. Lett. 2023, 14, 11274−11280; J. Phys. Chem. Lett. 2024, 15, 2493−2498; ACS Nano 2024, 18, 11732−11739; J. Phys. Chem. Lett. 2024, 15, 5939−5946;

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