Dey Poulumi, Basu Saurabh, Kishore R
Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
J Phys Condens Matter. 2009 Sep 2;21(35):355602. doi: 10.1088/0953-8984/21/35/355602. Epub 2009 Aug 10.
The Fulde-Ferrell-Larkin-Ovichinnikov (FFLO) phase is investigated in a two-dimensional superconductor described by a negative- U Hubbard model in the presence of a magnetic field. The parameter space defined by interparticle attraction and band filling is investigated and a search is performed for the FFLO phase therein, so as to provide clues to experiments designed to confirm the existence of a nonuniform spatial nature of the superconducting state. Our results convincingly demonstrate periodic modulation of the local pairing gap in real space. Heavy fermions, considered as a probable candidate that hosts the FFLO phase, are found in a metallurgically clean state and shows extreme type-II behaviour. In our calculations both these conditions are satisfied for a certain magnetic field range and the range expands for large interacting strengths and particle densities. The cleanliness condition is met as the coherence length becomes very small (compared to the mean free path) and the extreme type-II behaviour shows up via a large Ginzburg-Landau parameter.
在存在磁场的情况下，利用负U哈伯德模型描述的二维超导体中研究了富尔德-费雷尔-拉金-奥维奇尼科夫（FFLO）相。研究了由粒子间吸引和能带填充定义的参数空间，并在其中搜索FFLO相，以便为旨在证实超导态非均匀空间性质存在的实验提供线索。我们的结果令人信服地证明了实空间中局部配对能隙的周期性调制。重费米子被认为是承载FFLO相的一个可能候选者，它处于冶金学清洁状态并表现出极端的II型行为。在我们的计算中，对于一定的磁场范围，这两个条件都得到满足，并且随着相互作用强度和粒子密度的增大，该范围会扩大。当相干长度变得非常小（与平均自由程相比）时满足清洁条件，并且通过大的金兹堡-朗道参数表现出极端的II型行为。
