Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 61: Ultrafast Dynamics of Light-Driven Systems (joint session TT/MA)

TT 61.1: Talk

Thursday, March 19, 2020, 15:00–15:15, HSZ 201

Out-of-equilibrium magnetism of Sr₂IrO₄ and La₂CuO₄ — •Ekaterina Paerschke¹, Yao Wang², and Cheng-Chien Chen³ — ¹Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria — ²Department of Physics, Harvard University, Cambridge 02138, USA — ³Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA

Ultrafast pump-probe spectroscopy is an efficient tool to characterize and control strongly correlated materials due to its accessibility to both low-energy physics of the equilibrium phase and the novel excited states induced by the pump. Here, we investigate the ultrafast control of quantum magnetism in a half-filled Mott insulator, described by an extended Heisenberg model. This study reveals photo-manipulated magnetic properties for two archetypal Mott insulators: iridate Sr₂IrO₄ and cuprate La₂CuO₄. Understanding photo-manipulated spin fluctuations in cuprates and iridates can help to solve the long-standing question of superconductivity absence in the iridates, as spin fluctuations are believed to mediate superconductivity in transitional metal oxides. Starting from a broken-symmetry phase with a (π,π) ordering vector, we find that the various pump conditions can manipulate the competition with the subleading colinear AFM phase. Through the comparison of quantum quench simulations and Floquet analytical theory, we conclude that these manipulations are achieved through transient engineering of effective spin-exchange interactions.