Electron–Phonon Mechanism for Superconductivity in Na0.35CoO2: Valence-Band Suhl–Kondo Effect Driven by Shear Phonons

• Yada Keiji

  Department of Physics, Nagoya University

• Kontani Hiroshi

  Department of Physics, Nagoya University

Bibliographic Information

Other Title

• Electron–Phonon Mechanism for Superconductivity in Na_0.35CoO₂: Valence-Band Suhl–Kondo Effect Driven by Shear Phonons

Abstract

To study the possible mechanism of superconductivity in Na_0.35CoO₂, we examine the interaction between all the relevant optical phonons (breathing and shear phonons) and t_2g (a_1g+e_g′) electrons of Co ions, and study the transition temperature for s-wave superconductivity. The obtained T_c is very low when the e_g′ valence bands are far below the Fermi level. However, T_c is strongly enhanced when the top of the e_g′ valence bands is close to the Fermi level (e.g., −50 meV), thanks to the interband hopping of Cooper pairs caused by shear phonons. This “valence-band Suhl–Kondo mechanism” due to shear phonons is important in understanding the superconductivity in Na_0.35CoO₂. By the same mechanism, the kink structure of the band dispersion observed by angle-resolved photoemission spectroscopy (ARPES) measurements, which indicates the strong mass enhancement (m^*⁄m∼3) due to optical phonons, is also explained.

Journal

• Journal of the Physical Society of Japan

  Journal of the Physical Society of Japan 75 (3), 033705-, 2006

  THE PHYSICAL SOCIETY OF JAPAN

Keywords

• Na<I><SUB>x</SUB></I>CoO<SUB>2</SUB>
• electron–phonon coupling
• valence-band Suhl–Kondo effect
• shear phonon

Details

• CRID: 1390282679166499456
• NII Article ID: 110004704666
• NII Article ID: 210000106028
• NII Book ID: AA00704814
• DOI: 10.1143/jpsj.75.033705
• BIBCODE: 2006JPSJ...75c3705Y
• ISSN: 13474073
• ISSN: 00319015
• NDL BIB ID: 7852223
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7852223
• Web Site: http://journals.jps.jp/doi/pdf/10.1143/JPSJ.75.033705
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed