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Tunneling density of states of MgB2: evidence for a dominant π-band contribution

Alexander V. Abaloshev 2S. J. Lewandowski 2Alexander I. D’yachenko 1Vladimir Y. Tarenkov 1Mikhail A. Belogolovskii 1

1. National Academy of Sciences of Ukraine, A.Galkin Donetsk Institute for Physics & Technology (DonPTI NASU), Roza Luxemburg 72, Donetsk 83114, Ukraine
2. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland

Abstract

Weakly-transmitting junctions usable for tunneling spectroscopy experiments were fabricated from polycrystalline samples of magnesium diboride with a niobium counter-electrode. A strong nonlinear conductance-versus-voltage behavior for voltages above the values corresponding to the energy gaps of the electrodes was interpreted as a fingerprint of the electron-phonon interaction in superconducting MgB2. A partial Eliashberg spectral function α2(ω)F(ω) was extracted from the data by the numeric inversion of the standard strong-coupling Eliashberg equations. In a full agreement with recent theoretical simulations for magnesium diboride [O. V. Dolgov et al., PRB 68, 132503 (2003)], we have observed a dominant contribution from the π-band of this two-band superconductor.

 

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Related papers

Presentation: poster at E-MRS Fall Meeting 2004, Symposium E, by Alexander V. Abaloshev
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-05-01 19:07
Revised:   2009-06-08 12:55