Magnetic-field dependence of the gaps in a two-band superconductor: A point-contact study of MgB2 single crystalsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 29 мая 2015 г.
Аннотация:We present the results of directional point-contact measurements in MgB2 single crystals, in magnetic fields up to 9 T parallel to the c axis. By fitting the conductance curves of our point contacts-showing clear Andreev-reflection features-with a generalized Blonder-Tinkham-Klapwijk model, we extracted the values of the two gaps Delta(sigma) and Delta(pi). The resulting Delta(sigma)(B) and Delta(pi)(B) curves agree very well with the predictions of the two-band model in dirty limit when the pi-band diffusivity is a few times greater than the sigma-band one. This result concurs with other experimental and theoretical findings in indicating that, even in the best crystals, the pi band is moderately dirty.