Title: THz driven ultrafast processes in quantum materials
Speaker: Prof. Shovon Pal, NISER Bhubaneswar
Abstract: Quantum materials – a category of condensed matter systems – display strong electronic correlations where the very notion of electrons as non-interacting entities fails. The properties of quantum materials with the so-called strongly correlated states are, instead, determined by the collective interaction of many electrons via their charges and spins [1,2]. The complexity that arises from such interactions gives rise to emergent phenomena in a multitude of quantum materials, like high-Tc superconductors [3], heavy-fermion materials [4,5], ferroelectrics [6], topological materials [7], and multiferroics [8]. Because of the multi-particle nature, microscopic understanding of their ground states with such strong-correlation phenomena is a demanding task and requires going away from the ground state and studying the non- equilibrium dynamics of such systems. In general, equilibrium studies ignore the temporal evolution of a physical process, and most importantly, neglect local fluctuations in the systems. In contrast, the non-equilibrium descriptions explain the roles of such fluctuations both in time and space. As the dynamics of many-body processes get even more critical in various quantum materials, we need to understand how the temporal evolutions of specific processes affect the underlying correlations between charge, spin, lattice and orbital degrees of freedom. In this talk, I will provide an overview on how the THz light has been used to drive quantum materials out of equilibrium and gain information on the associated correlation processes and the dynamics of low-energy excitations [9].
References: [1] D. N. Basov, et al., Rev. Mod. Phys., 83, 471 (2011).
[2] B. Keimer, et al., Nat. Phys. 13, 1045 (2017).
[3] M. Budden, et al., Nat. Phys. 17, 611 (2021).
[4] C. Wetli, et al., Nat. Phys. 14, 1103 (2018).
[5] C.-J. Yang, et al., Nat. Phys. (2023).
[6] X. Li, et al., Science 364, 1079 (2019).
[7] J. Reimann, et al., Nature 562, 396 (2018).
[8] T. Kubacka, et al., Science 343, 1333 (2014).
[9] C.-J. Yang, et al., Nat. Rev. Mat. 8, 518 (2023).