Instituto de Física, Universidade Federal Fluminense, Campus da Praia Vermelha, Niterói, RJ, 24.210-340, Brazil.
J Phys Condens Matter. 2011 Mar 30;23(12):125701. doi: 10.1088/0953-8984/23/12/125701. Epub 2011 Mar 10.
In multi-band metals quasi-particles arising from different atomic orbitals coexist at a common Fermi surface. Superconductivity in these materials may appear due to interactions within a band (intra-band) or among the distinct metallic bands (inter-band). Here we consider the suppression of superconductivity in the intra-band case due to hybridization. The fluctuations at the superconducting quantum critical point (SQCP) are obtained by calculating the response of the system to a fictitious space- and time-dependent field, which couples to the superconducting order parameter. The appearance of superconductivity is related to the divergence of a generalized susceptibility. For a single-band superconductor this coincides with the Thouless criterion. For fixed chemical potential and large hybridization, the superconducting state has many features in common with breached pair superconductivity with unpaired electrons at the Fermi surface. The T = 0 phase transition from the superconductor to the normal state is in the universality class of the density-driven Bose-Einstein condensation. For a fixed number of particles and in the strong coupling limit, the system still has an instability to the normal state with increasing hybridization.
在多带金属中，来自不同原子轨道的准粒子在共同的费米表面共存。这些材料中的超导性可能是由于带内（带内）或不同金属带之间的相互作用（带间）引起的。在这里，我们考虑由于杂化导致带内超导性的抑制。通过计算系统对与超导序参量耦合的虚构空间和时间相关场的响应来获得超导量子临界点（SQCP）的涨落。超导性的出现与广义磁化率的发散有关。对于单带超导体，这与图卢兹准则一致。对于固定的化学势和大的杂化，超导态与费米面处未配对电子的破裂对超导性具有许多共同特征。从超导态到正常态的 T=0 相变属于密度驱动玻色-爱因斯坦凝聚的通用类。对于固定数量的粒子和强耦合极限，随着杂化的增加，系统仍然对正常态不稳定。
