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Condensed Matter > Strongly Correlated Electrons
Title: Effects of renormalization and non-Hermiticity on nonlinear responses in strongly-correlated electron systems
(Submitted on 19 Dec 2020 (v1), last revised 16 May 2021 (this version, v3))
Abstract: Nonlinear responses in condensed matter are intensively studied because they provide rich information about materials and hold the possibility of being applied in diodes or high-frequency optical devices. While nonlinear responses in noninteracting models have been explored widely, the effect of strong correlations on the nonlinear response is still poorly understood, even though it has been suggested that correlations can enhance the nonlinear response. In this work, we first give an analytical derivation of nonlinear responses using the Green's function methods at finite temperature. Then, we discuss the difficulties of considering dissipation using conventional methods, such as the reduced density matrix method. We reveal that the relaxation time approximation leads to severe limitations when considering optical responses. Finally, we demonstrate that correlation effects, such as the renormalization of the band structure and different lifetime in orbitals or sublattices, can significantly enhance nonlinear responses and can even change the sign of the nonlinear conductivity.
Submission history
From: Yoshihiro Michishita [view email][v1] Sat, 19 Dec 2020 06:20:42 GMT (1450kb,D)
[v2] Mon, 25 Jan 2021 04:20:39 GMT (1387kb,D)
[v3] Sun, 16 May 2021 07:33:16 GMT (3723kb,D)
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