Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory

Tom G. Saunderson; James F. Annett; Balázs Újfalussy; Gábor Csire; Martin Gradhand

doi:10.1103/PhysRevB.101.064510

Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory

Tom G. Saunderson, James F. Annett, Balázs Újfalussy, Gábor Csire, Martin Gradhand

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Abstract

We implement the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn-Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals. This method combines the full complexity of the underlying electronic structure and Fermi surface geometry with a simple phenomenological parametrisation for the superconductivity. We apply this theoretical framework to the known s-wave superconductors Nb, Pb, and MgB$_2$. In these materials multiple distinct peaks at the gap in the density of states were observed, showing significant gap anisotropy which is in good agreement with experiment. Qualitatively, the results can be explained in terms of the k-dependent Fermi velocities on the Fermi surface sheets exploiting concepts from BCS theory.

Original language	English
Article number	064510
Pages (from-to)	1-9
Journal	Physical Review B
Volume	101
Issue number	6
DOIs	https://doi.org/10.1103/PhysRevB.101.064510
Publication status	Published - 18 Feb 2020

Keywords

cond-mat.supr-con
Fermi surface
Multiband superconductivity
Ab initio calculations
Bogoliubov-de Gennes equations
Korringa-Khon-Rostoker method

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10.1103/PhysRevB.101.064510

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@article{31f4982632d44570af129a7682c50f5e,

title = "Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory",

abstract = "We implement the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn-Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals. This method combines the full complexity of the underlying electronic structure and Fermi surface geometry with a simple phenomenological parametrisation for the superconductivity. We apply this theoretical framework to the known s-wave superconductors Nb, Pb, and MgB$_2$. In these materials multiple distinct peaks at the gap in the density of states were observed, showing significant gap anisotropy which is in good agreement with experiment. Qualitatively, the results can be explained in terms of the k-dependent Fermi velocities on the Fermi surface sheets exploiting concepts from BCS theory. ",

keywords = "cond-mat.supr-con, Fermi surface, Multiband superconductivity, Ab initio calculations, Bogoliubov-de Gennes equations, Korringa-Khon-Rostoker method",

author = "Saunderson, {Tom G.} and Annett, {James F.} and Bal{\'a}zs {\'U}jfalussy and G{\'a}bor Csire and Martin Gradhand",

year = "2020",

month = feb,

day = "18",

doi = "10.1103/PhysRevB.101.064510",

language = "English",

volume = "101",

pages = "1--9",

journal = "Physical Review B",

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publisher = "American Physical Society (APS)",

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TY - JOUR

T1 - Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory

AU - Saunderson, Tom G.

AU - Annett, James F.

AU - Újfalussy, Balázs

AU - Csire, Gábor

AU - Gradhand, Martin

PY - 2020/2/18

Y1 - 2020/2/18

N2 - We implement the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn-Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals. This method combines the full complexity of the underlying electronic structure and Fermi surface geometry with a simple phenomenological parametrisation for the superconductivity. We apply this theoretical framework to the known s-wave superconductors Nb, Pb, and MgB$_2$. In these materials multiple distinct peaks at the gap in the density of states were observed, showing significant gap anisotropy which is in good agreement with experiment. Qualitatively, the results can be explained in terms of the k-dependent Fermi velocities on the Fermi surface sheets exploiting concepts from BCS theory.

AB - We implement the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn-Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals. This method combines the full complexity of the underlying electronic structure and Fermi surface geometry with a simple phenomenological parametrisation for the superconductivity. We apply this theoretical framework to the known s-wave superconductors Nb, Pb, and MgB$_2$. In these materials multiple distinct peaks at the gap in the density of states were observed, showing significant gap anisotropy which is in good agreement with experiment. Qualitatively, the results can be explained in terms of the k-dependent Fermi velocities on the Fermi surface sheets exploiting concepts from BCS theory.

KW - cond-mat.supr-con

KW - Fermi surface

KW - Multiband superconductivity

KW - Ab initio calculations

KW - Bogoliubov-de Gennes equations

KW - Korringa-Khon-Rostoker method

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U2 - 10.1103/PhysRevB.101.064510

DO - 10.1103/PhysRevB.101.064510

M3 - Article (Academic Journal)

SN - 2469-9950

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SP - 1

EP - 9

JO - Physical Review B

JF - Physical Review B

IS - 6

M1 - 064510

ER -

Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory

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Rework of Novel orders in unconventional superconductors: new paradigms for new classes of materials

The effect of impurities on the superconducting state

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Gap Anisotropy in Multiband Superconductors Based on Multiple Scattering Theory

Abstract

Keywords

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Rework of Novel orders in unconventional superconductors: new paradigms for new classes of materials

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The effect of impurities on the superconducting state

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