Quasiparticle Fermi surfaces of niobium and niobium-titanium alloys at high pressure

Fuente: arXiv
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Autores principales: Jones, D., Östlin, A., Chmeruk, A., Beiuşeanu, F., Eckern, U., Vitos, L., Chioncel, L.
Formato: Preprint
Publicado: 2025
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author Jones, D.
Östlin, A.
Chmeruk, A.
Beiuşeanu, F.
Eckern, U.
Vitos, L.
Chioncel, L.
author_facet Jones, D.
Östlin, A.
Chmeruk, A.
Beiuşeanu, F.
Eckern, U.
Vitos, L.
Chioncel, L.
contents The electronic structure of pure niobium and the niobium-titanium alloy Nb$_{0.44}$Ti$_{0.56}$ in the bcc-phase at pressures up to $250$ GPa is investigated, to reveal possible factors conducing toward the robust superconductivity reported for Ti-doped niobium upon a considerable volume reduction. We model the structural disorder using the coherent potential approximation, and the electronic correlations are taken into account using dynamical mean-field theory. At high pressure, a significant change in the topology of the Fermi surface is observed, while electronic correlations weaken with increasing pressure. Thus, the normal state of Nb$_{0.44}$Ti$_{0.56}$ is found to be a Fermi liquid with a well-defined Fermi surface, and well-defined quasiparticles near it. The systematic study of the impact of disorder upon the Fermi surface at such ultra high pressures allows notable insights into the nature of the electronic states near the Fermi level, i.e., within the energy scale relevant for superconducting pairing. Furthermore, our results clearly indicate the necessity of further experimental Fermi surface explorations.
format Preprint
id arxiv_https___arxiv_org_abs_2501_08012
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quasiparticle Fermi surfaces of niobium and niobium-titanium alloys at high pressure
Jones, D.
Östlin, A.
Chmeruk, A.
Beiuşeanu, F.
Eckern, U.
Vitos, L.
Chioncel, L.
Superconductivity
Strongly Correlated Electrons
The electronic structure of pure niobium and the niobium-titanium alloy Nb$_{0.44}$Ti$_{0.56}$ in the bcc-phase at pressures up to $250$ GPa is investigated, to reveal possible factors conducing toward the robust superconductivity reported for Ti-doped niobium upon a considerable volume reduction. We model the structural disorder using the coherent potential approximation, and the electronic correlations are taken into account using dynamical mean-field theory. At high pressure, a significant change in the topology of the Fermi surface is observed, while electronic correlations weaken with increasing pressure. Thus, the normal state of Nb$_{0.44}$Ti$_{0.56}$ is found to be a Fermi liquid with a well-defined Fermi surface, and well-defined quasiparticles near it. The systematic study of the impact of disorder upon the Fermi surface at such ultra high pressures allows notable insights into the nature of the electronic states near the Fermi level, i.e., within the energy scale relevant for superconducting pairing. Furthermore, our results clearly indicate the necessity of further experimental Fermi surface explorations.
title Quasiparticle Fermi surfaces of niobium and niobium-titanium alloys at high pressure
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2501.08012