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arXiv · 2003.09653

Non-equilibrium Properties of Berezinskii-Kosterlitz-Thouless Phase Transitions

Christian Klöckner·Christoph Karrasch·Dante Marvin Kennes
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Abstract

We employ a novel, unbiased renormalization-group approach to investigate non-equilibrium phase transitions in infinite lattice models. This allows us to address the delicate interplay of fluctuations and ordering tendencies in low dimensions out of equilibrium. We study a prototypical model for the metal to insulator transition of spinless interacting fermions coupled to electronic baths and driven out of equilibrium by a longitudinal static electric field. The closed system features a Berezinskii-Kosterlitz-Thouless transition between a metallic and a charge-ordered phase in the equilibrium limit. We compute the non-equilibrium phase diagram and illustrate a highly non-monotonic dependence of the phase boundary on the strength of the electric field: For small fields, the induced currents destroy the charge order, while at higher electric fields it reemerges due to many-body Wannier-Stark localization physics. Finally, we show that the current in such an interacting non-equilibrium system can counter-intuitively flow opposite to the direction of the electric field. This non-equilibrium steady-state is reminiscent of an equilibrium distribution function with an effective negative temperature.

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Christian Klöckner, Christoph Karrasch, Dante Marvin Kennes. 2020-11-16. Non-equilibrium Properties of Berezinskii-Kosterlitz-Thouless Phase Transitions. https://doi.org/10.1103/physrevlett.125.147601

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