Superconductivity driven by the interband Coulomb interaction and implications for the superconducting mechanism of MgB2

Masatoshi Imada

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Superconducting mechanism mediated by interband exchange Coulomb repulsion is examined in an extended two-band Hubbard models with a wide band crossing the Fermi level and coexisting with a narrower band located at moderately lower energy. We apply newly developed path-integral renormalization group method to reliably calculate pairing correlations. The correlation shows marked enhancement at moderate amplitudes of the exchange Coulomb repulsion taken smaller than the on-site repulsion for the narrower band. The pairing symmetry is s-wave while it has unconventional phases with the opposite sign between the order parameters on the two bands, in agreement with the mean-field prediction. Since the band structure of recently discovered superconductor MgB2 shares basic similarities with our model, we propose that the present results provide a relevant clue for the understanding of the superconducting mechanism in MgB2 as well as in this class of multi-band materials with good metallic conduction in the normal state.

Original languageEnglish
Pages (from-to)1218-1221
Number of pages4
JournalJournal of the Physical Society of Japan
Volume70
Issue number5
DOIs
Publication statusPublished - 2001 May 1
Externally publishedYes

Fingerprint

superconductivity
narrowband
interactions
renormalization group methods
broadband
conduction
augmentation
symmetry
predictions
energy

Keywords

  • Exchange Coulomb interaction
  • Interband pairing
  • MgB
  • Pairing mechanism
  • Unconventional superconductor

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Superconductivity driven by the interband Coulomb interaction and implications for the superconducting mechanism of MgB2. / Imada, Masatoshi.

In: Journal of the Physical Society of Japan, Vol. 70, No. 5, 01.05.2001, p. 1218-1221.

Research output: Contribution to journalArticle

@article{099c95647c4245679122f29c1a750fb8,
title = "Superconductivity driven by the interband Coulomb interaction and implications for the superconducting mechanism of MgB2",
abstract = "Superconducting mechanism mediated by interband exchange Coulomb repulsion is examined in an extended two-band Hubbard models with a wide band crossing the Fermi level and coexisting with a narrower band located at moderately lower energy. We apply newly developed path-integral renormalization group method to reliably calculate pairing correlations. The correlation shows marked enhancement at moderate amplitudes of the exchange Coulomb repulsion taken smaller than the on-site repulsion for the narrower band. The pairing symmetry is s-wave while it has unconventional phases with the opposite sign between the order parameters on the two bands, in agreement with the mean-field prediction. Since the band structure of recently discovered superconductor MgB2 shares basic similarities with our model, we propose that the present results provide a relevant clue for the understanding of the superconducting mechanism in MgB2 as well as in this class of multi-band materials with good metallic conduction in the normal state.",
keywords = "Exchange Coulomb interaction, Interband pairing, MgB, Pairing mechanism, Unconventional superconductor",
author = "Masatoshi Imada",
year = "2001",
month = "5",
day = "1",
doi = "10.1143/JPSJ.70.1218",
language = "English",
volume = "70",
pages = "1218--1221",
journal = "Journal of the Physical Society of Japan",
issn = "0031-9015",
publisher = "Physical Society of Japan",
number = "5",

}

TY - JOUR

T1 - Superconductivity driven by the interband Coulomb interaction and implications for the superconducting mechanism of MgB2

AU - Imada, Masatoshi

PY - 2001/5/1

Y1 - 2001/5/1

N2 - Superconducting mechanism mediated by interband exchange Coulomb repulsion is examined in an extended two-band Hubbard models with a wide band crossing the Fermi level and coexisting with a narrower band located at moderately lower energy. We apply newly developed path-integral renormalization group method to reliably calculate pairing correlations. The correlation shows marked enhancement at moderate amplitudes of the exchange Coulomb repulsion taken smaller than the on-site repulsion for the narrower band. The pairing symmetry is s-wave while it has unconventional phases with the opposite sign between the order parameters on the two bands, in agreement with the mean-field prediction. Since the band structure of recently discovered superconductor MgB2 shares basic similarities with our model, we propose that the present results provide a relevant clue for the understanding of the superconducting mechanism in MgB2 as well as in this class of multi-band materials with good metallic conduction in the normal state.

AB - Superconducting mechanism mediated by interband exchange Coulomb repulsion is examined in an extended two-band Hubbard models with a wide band crossing the Fermi level and coexisting with a narrower band located at moderately lower energy. We apply newly developed path-integral renormalization group method to reliably calculate pairing correlations. The correlation shows marked enhancement at moderate amplitudes of the exchange Coulomb repulsion taken smaller than the on-site repulsion for the narrower band. The pairing symmetry is s-wave while it has unconventional phases with the opposite sign between the order parameters on the two bands, in agreement with the mean-field prediction. Since the band structure of recently discovered superconductor MgB2 shares basic similarities with our model, we propose that the present results provide a relevant clue for the understanding of the superconducting mechanism in MgB2 as well as in this class of multi-band materials with good metallic conduction in the normal state.

KW - Exchange Coulomb interaction

KW - Interband pairing

KW - MgB

KW - Pairing mechanism

KW - Unconventional superconductor

UR - http://www.scopus.com/inward/record.url?scp=0035625550&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035625550&partnerID=8YFLogxK

U2 - 10.1143/JPSJ.70.1218

DO - 10.1143/JPSJ.70.1218

M3 - Article

AN - SCOPUS:0035625550

VL - 70

SP - 1218

EP - 1221

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - 5

ER -