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Damping of the de Haas-van Alphen oscillations in the superconducting state of MgB_2

J. D. Fletcher·A. Carrington·S. M. Kazakov·J. Karpinski
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Abstract

The de Haas-van Alphen (dHvA) signal arising from orbits on the $π$ Fermi surface sheet of the two-gap superconductor MgB$_2$ has been observed in the vortex state below $H_{c2}$. An extra attenuation of the dHvA signal, beyond those effects described in the conventional Lifshitz-Kosevich expression, is seen due to the opening of the superconducting gap. Our data show that the $π$ band gap is still present up to $H_{c2}$. The data are compared to current theories of dHvA oscillations in the superconducting state which allow us to extract estimates for the evolution of the $π$ band gap with magnetic field. Contrary to results for other materials, we find that the most recent theories dramatically underestimate the damping in MgB$_2$.

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J. D. Fletcher, A. Carrington, S. M. Kazakov, J. Karpinski. 2004-05-06. Damping of the de Haas-van Alphen oscillations in the superconducting state of MgB_2. https://doi.org/10.1103/physrevb.70.144501

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