20
JUNI
JUNI
Revisiting electron-phonon coupling and polaron physics in the bismuthate superconductors
Seminar
Spezialisiert / Akademisch
20.06.2025 11:00
Präsenzveranstaltung
Despite decades of study, the underlying pairing mechanism in the bismuthate family Ba1-xKxBiO3 (BKBO) of high-temperature superconductors remains unresolved. In this talk, I will discuss recent work reexamining the role of electron-phonon coupling in this system, both in the parent and doped compounds. I will begin by presenting new nonperturbative hybrid Monte Carlo calculations (HMC) for a multi-orbital model that includes the Bi 6s and O 2p orbitals with coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the hopping integrals [1]. Using a state-of-the-art HMC implementation [2], we treat large three-dimensional clusters of up to 4000 orbitals with realistic model parameters taken from ab initio electronic structure calculations. Our results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in the parent compound and highlight the critical role played by the bond-stretching oxygen modes. I will then discuss the results for the doped system in conjunction with new total neutron and resonant inelastic x-ray scattering measurements [3]. Here, we find evidence for a (bi)polaronic normal state, implicating the bismuthates as a novel class of bipolaronic superconductors.
Wann?
20.06.2025 11:00
Wo?
Organisation
Département de Physique
Prof. Claude Monney
claude.monney@unifr.ch
Chemin du Musée 3
1700 Fribourg
0263009113
Prof. Claude Monney
claude.monney@unifr.ch
Chemin du Musée 3
1700 Fribourg
0263009113
Vortragende / Mitwirkende
Prof. Steven Johnston
University of Tennessee
University of Tennessee
Zurück zur Liste
« | Juli 2025 | » | ||||
---|---|---|---|---|---|---|
Mo | Di | Mi | Do | Fr | Sa | So |
30 | 1 | 2 | 3 | 4 | 5 | 6 |
7 | 8 | 9 | 10 | 11 | 12 | 13 |
14 | 15 | 16 | 17 | 18 | 19 | 20 |
21 | 22 | 23 | 24 | 25 | 26 | 27 |
28 | 29 | 30 | 31 | 1 | 2 | 3 |
4 | 5 | 6 | 7 | 8 | 9 | 10 |