Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x

Abstract The highest ambient‐pressure Tc among binary compounds is 40 K (MgB2). Higher Tc is achieved in high‐pressure hydrides or multielement cuprates. Alternatively, are explored superconducting properties of binary, metastable sub‐oxides, that may emerge under extremely low oxygen partial pressu...

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Main Authors: Pjotrs Žguns, Nuh Gedik, Bilge Yildiz, Ju Li
Format: Article
Language:English
Published: Wiley-VCH 2024-11-01
Series:Advanced Electronic Materials
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Online Access:https://doi.org/10.1002/aelm.202400141
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author Pjotrs Žguns
Nuh Gedik
Bilge Yildiz
Ju Li
author_facet Pjotrs Žguns
Nuh Gedik
Bilge Yildiz
Ju Li
author_sort Pjotrs Žguns
collection DOAJ
description Abstract The highest ambient‐pressure Tc among binary compounds is 40 K (MgB2). Higher Tc is achieved in high‐pressure hydrides or multielement cuprates. Alternatively, are explored superconducting properties of binary, metastable sub‐oxides, that may emerge under extremely low oxygen partial pressure. The emphasis is on the rock‐salt structure, which is known to promote superconductivity, and exploring AlO, ScO, TiO, and NbO. Dynamic lattice stability is achieved by introducing metal and oxygen vacancies in the fashion of Nb1−xO1−x‐type structure (x = ¼). The electron‐phonon (e‐ph) coupling is remarkably large in Al1−xO1−x and Ti1−xO1−x (λ ≈ 2 at x = ¼), with Tc ≈ 35 K according to the Allen–Dynes equation. Significantly, the coupling strength is comparable to that in high‐pressure hydrides, yet, in contrast to hydrides and MgB2, the coupling is largely driven by low frequency phonons. Sc1−xO1−x and Nb1−xO1−x show significantly smaller λ and Tc. Further, hydrogen intercalation to boost λ and Tc is investigated. Only Ti1−x(O1−xHx) and Nb1−x(O1−xHx) are dynamically stable upon intercalation, where H, respectively, decreases and increases Tc. The effect of H doping on electronic structure and Tc is discussed. Altogether, the study suggests that metal sub‐oxides are promising compounds to achieve strong e‐ph coupling at ambient pressure.
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spelling doaj-art-167da1fc390b44f4b909bbdbfe7ed12b2024-11-09T18:01:02ZengWiley-VCHAdvanced Electronic Materials2199-160X2024-11-011011n/an/a10.1002/aelm.202400141Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−xPjotrs Žguns0Nuh Gedik1Bilge Yildiz2Ju Li3Department of Materials Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139–4307 USADepartment of Physics 77 Massachusetts Avenue Cambridge MA 02139–4307 USADepartment of Materials Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139–4307 USADepartment of Materials Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139–4307 USAAbstract The highest ambient‐pressure Tc among binary compounds is 40 K (MgB2). Higher Tc is achieved in high‐pressure hydrides or multielement cuprates. Alternatively, are explored superconducting properties of binary, metastable sub‐oxides, that may emerge under extremely low oxygen partial pressure. The emphasis is on the rock‐salt structure, which is known to promote superconductivity, and exploring AlO, ScO, TiO, and NbO. Dynamic lattice stability is achieved by introducing metal and oxygen vacancies in the fashion of Nb1−xO1−x‐type structure (x = ¼). The electron‐phonon (e‐ph) coupling is remarkably large in Al1−xO1−x and Ti1−xO1−x (λ ≈ 2 at x = ¼), with Tc ≈ 35 K according to the Allen–Dynes equation. Significantly, the coupling strength is comparable to that in high‐pressure hydrides, yet, in contrast to hydrides and MgB2, the coupling is largely driven by low frequency phonons. Sc1−xO1−x and Nb1−xO1−x show significantly smaller λ and Tc. Further, hydrogen intercalation to boost λ and Tc is investigated. Only Ti1−x(O1−xHx) and Nb1−x(O1−xHx) are dynamically stable upon intercalation, where H, respectively, decreases and increases Tc. The effect of H doping on electronic structure and Tc is discussed. Altogether, the study suggests that metal sub‐oxides are promising compounds to achieve strong e‐ph coupling at ambient pressure.https://doi.org/10.1002/aelm.202400141BCS superconductivityelectron‐phonon couplingsub‐oxides
spellingShingle Pjotrs Žguns
Nuh Gedik
Bilge Yildiz
Ju Li
Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
Advanced Electronic Materials
BCS superconductivity
electron‐phonon coupling
sub‐oxides
title Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
title_full Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
title_fullStr Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
title_full_unstemmed Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
title_short Superconductivity and Pronounced Electron‐Phonon Coupling in Rock‐Salt Al1−xO1−x and Ti1−xO1−x
title_sort superconductivity and pronounced electron phonon coupling in rock salt al1 xo1 x and ti1 xo1 x
topic BCS superconductivity
electron‐phonon coupling
sub‐oxides
url https://doi.org/10.1002/aelm.202400141
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AT bilgeyildiz superconductivityandpronouncedelectronphononcouplinginrocksaltal1xo1xandti1xo1x
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