1202.2833 (Józef Spałek)

Theory of Unconventional Superconductivity in Strongly Correlated
Systems: Real Space Pairing and Statistically Consistent Mean-Field Theory -
in Perspective    [PDF]

Józef Spałek

In this brief overview we discuss the principal features of real space
pairing as expressed via corresponding low-energy (t-J or periodic
Anderson-Kondo) effective Hamiltonian, as well as consider concrete properties
of those unconventional superconductors. We also rise the basic question of
statistical consistency within the so-called renormalized mean-field theory. In
particular, we provide the phase diagrams encompassing the stable magnetic and
superconducting states. We interpret real space pairing as correlated motion of
fermion pair coupled by short-range exchange interaction of magnitude J
comparable to the particle renormalized band energy $\sim tx$, where $x$ is the
carrier number per site. We also discuss briefly the difference between the
real-space and the paramagnon - mediated sources of superconductivity. The
paper concentrates both on recent novel results obtained in our research group,
as well as puts the theoretical concepts in a conceptual as well as historical
perspective. No slave-bosons are required to formulate the present approach.

View original: http://arxiv.org/abs/1202.2833