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Nesting properties and anomalous band effect in MgB2

Izumi Hase·Kunihiko Yamaji
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Abstract

First principle FLAPW band calculations of the new superconductor MgB2 were performed and the polarization function P12(Q) between the two p-bands mainly formed of boron pz-orbital was calculated. We found that P12(Q) is substantially enhanced around Q=(0,0,p/c), which supports the two-band mechanism of superconductivity for MgB2. P12(Q) peaks at Qz ~ 0.3(2p/c) and Qz \~ 0.5(2p/c). These two peaks are related to the nesting of these Fermi surfaces, but significantly deviates from the position expected from the simplest tight-binding bands for the p-bands. From the calculations for different lattice parameters, we have found significant dependences on the isotopic species of B and on the pressure effect of the polarization function in accordance with the respective changes of Tc in the above-mentioned framework.

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Izumi Hase, Kunihiko Yamaji. 2001-06-29. Nesting properties and anomalous band effect in MgB2. https://doi.org/10.1143/jpsj.70.2376

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