26ème Congrès Général de la SFP

Multi-channel fluctuating field approach to interplaying collective fluctuations in strongly correlated systems

Non programmé

20m

Centre des Congrès de la Villette (Cité des sciences et de l'Industrie, Paris)

Poster MC21 Matériaux quantiques : des prédictions à l'observation Session Poster 2: MC1, MC4, MC8, MC10, MC12, MC14, MC20, MC21, MC23, MC24, MC25, REDP

Orateur

Erik Linnér (CPHT, École Polytechnique, CNRS, Institut Polytechnique de Paris)

Description

Correlated fermion systems often display complex phase diagrams with different competing orderings. A theoretical description of competing instabilities remains one of the major challenges of modern condensed matter physics. We introduce a multi-channel extension of the recently developed fluctuating field approach to tackle this problem, based on a variational optimisation of a trial action that explicitly contains the leading fluctuations channels [1]. Application of the approach to the extended Hubbard models captures the interplay of competing charge density wave, antiferromagnetism, s-wave superconductivity, and phase separation fluctuations [1,2]. For the case of the attractive model, our approach has allowed us to identify a novel phase that is characterised by the coexistence of s-wave superconductivity and phase separation [2]. Our findings resonate with previous observations of interplaying phase separation and superconducting phases in electronic systems, most importantly in high-temperature superconductors.

References :
[1] E. Linnér, A. I. Lichtenstein, S. Biermann, E. A. Stepanov, arXiv:2210.05540 (2022).
[2] E. Linnér, C. Dutreix, S. Biermann, E. A. Stepanov, arXiv:2301.10755 (2023).