We study the interplay between electron-electron interaction and a Jahn-Teller phonon coupling in a two -orbital Hubbard model. We demonstrate that the e-ph interaction coexists with the Mott localization driven by the Hubbard repulsion U, but it competes with the Hund's coupling J. This interplay leads to two spectacularly different Mott insulators, a standard high-spin Mott insulator with frozen phonons which is stable when the Hund's coupling prevails, and a low-spin Mott-bipolaronic insulator favored by phonons, where the characteristic features of Mott insulators and bipolarons coexist. The two phases are separated by a sharp boundary along which an intriguing intermediate solution emerges as a kind of compromise between the two solutions.

Competing correlated insulators in multiorbital systems coupled to phonons / Scazzola, Alberto; Amaricci, Adriano; Capone, Massimo. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 107:8(2023), pp. 1-6. [10.1103/PhysRevB.107.085131]

Competing correlated insulators in multiorbital systems coupled to phonons

Scazzola, Alberto;Amaricci, Adriano;Capone, Massimo
2023-01-01

Abstract

We study the interplay between electron-electron interaction and a Jahn-Teller phonon coupling in a two -orbital Hubbard model. We demonstrate that the e-ph interaction coexists with the Mott localization driven by the Hubbard repulsion U, but it competes with the Hund's coupling J. This interplay leads to two spectacularly different Mott insulators, a standard high-spin Mott insulator with frozen phonons which is stable when the Hund's coupling prevails, and a low-spin Mott-bipolaronic insulator favored by phonons, where the characteristic features of Mott insulators and bipolarons coexist. The two phases are separated by a sharp boundary along which an intriguing intermediate solution emerges as a kind of compromise between the two solutions.
2023
107
8
1
6
085131
Scazzola, Alberto; Amaricci, Adriano; Capone, Massimo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/137490
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