Fermi Surfaces of Diborides: MgB2 and ZrB2

Abstract

We provide a comparison of accurate full potential band calculations of the Fermi surfaces areas and masses of MgB2 and ZrB2 with the de Haas-van Alphen date of Yelland et al. and Tanaka et al., respectively. The discrepancies in areas in MgB2 can be removed by a shift of sigma-bands downward with respect to pi-bands by 0.24 eV. Comparison of effective masses lead to orbit averaged electron-phonon coupling constants lambda(sigma)=1.3 (both orbits), lambda(pi)=0.5. The required band shifts, which we interpret as an exchange attraction for sigma states beyond local density band theory, reduces the number of holes from 0.15 to 0.11 holes per cell. This makes the occurrence of superconductivity in MgB2 a somewhat closer call than previously recognized, and increases the likelihood that additional holes can lead to an increased Tc.

7 pages including 4 figures

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Cited by in corpus (20)

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• The two colors of MgB2
• Determination of the Fermi Surface of MgB${}_2$ by the de Haas-van Alphen effect
• First-principles Calculation of Superconductivity in Hole-doped LiBC: $T_c=65$ K
• Born Effective Charges and Infrared Response of LiBC
• Comparative study of the electronic structure, phonon spectra and electron-phonon interaction of ZrB2 and TiB2
• Extreme Electron-Phonon Coupling in Boron-based Layered Superconductors
• Multiband and impurity effects in infrared and optical spectra of MgB2
• X-ray photoelectron spectroscopy studies of non-stoichiometric superconducting NbB2+x
• Surface states and their possible role in the superconductivity of MgB2
• de Haas-van Alphen effect investigation of the electronic structure of Al substituted MgB_2
• Effect of metal vacancies on the electronic band structure of hexagonal Nb, Zr and Y diborides
• Electronic Structure of B-2$p\sigma$ and $p\pi$ States in MgB${}_2$, AlB${}_2$ and ZrB${}_2$ Single Crystals
• Damping of the de Haas-van Alphen oscillations in the superconducting state of MgB_2
• de Haas-van Alphen effect investigations of the electronic structure of pure and aluminum-doped MgB_2
• On Electron Transport in ZrB12, ZrB2 and MgB2
• Theoretical Study of Electron-Phonon Interaction in ZrB2 and TaB2
• Interpretation of the angular dependence of the de Haas-van Alphen effect in MgB_2
• Pressure Effects and Large Polarons in Layered MgB_2 Superconductor