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arXiv · 0710.2382

Flux Line Lattice Melting and the Formation of a Coherent Quasiparticle Bloch State in the Ultraclean URu$_2$Si$_2$ Superconductor

R. Okazaki·Y. Kasahara·H. Shishido·M. Konczykowski·K. Behnia·Y. Haga·T. D. Matsuda·Y. Onuki·T. Shibauchi·Y. Matsuda
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Abstract

We find that in ultraclean heavy-fermion superconductor URu$_2$Si$_2$ ($T_{c0}=1.45$ K) a distinct flux line lattice melting transition with outstanding characters occurs well below the mean-field upper critical fields. We show that a very small number of carriers with heavy mass in this system results in exceptionally large thermal fluctuations even at subkelvin temperatures, which are witnessed by a sizable region of the flux line liquid phase. The uniqueness is further highlighted by an enhancement of the quasiparticle mean free path below the melting transition, implying a possible formation of a quasiparticle Bloch state in the periodic flux line lattice.

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R. Okazaki, Y. Kasahara, H. Shishido, M. Konczykowski, K. Behnia, Y. Haga, T. D. Matsuda, Y. Onuki, T. Shibauchi, Y. Matsuda. 2007-12-16. Flux Line Lattice Melting and the Formation of a Coherent Quasiparticle Bloch State in the Ultraclean URu$_2$Si$_2$ Superconductor. https://doi.org/10.1103/physrevlett.100.037004

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