Seminar on Disorder & Strong Electron Correlations 26 January 2012

[ivanisse]

CONDENSED MATTER AND STATISTICAL PHYSICS SECTION

Seminar on Disorder and strong electron correlations


Thursday, 26 January 2012  -   11:30 a.m.


Luigi Stasi Seminar Room - ICTP Leonardo Bldg. - 1st floor


Andrey VARLAMOV (Università di Roma II, CNR-SPIN, Roma)

" Quantum Fluctuations and Dynamic Clustering of Fluctuating Cooper Pairs "

Abstract:

We derive the exact expressions for the fluctuation conductivity in two 
dimensional superconductors as a function of temperature and magnetic 
field in the whole phase diagram above the upper critical field line 
Hc2(T). Focusing on the vicinity of the quantum phase transition near 
zero temperature we arrive to the conclusion that as the magnetic field 
approaches the critical field Hc2(0) from above, a peculiar dynamic 
state consisting of clusters of coherently rotating fluctuation 
Cooper-pairs forms. We estimate the characteristic size  QF( H)  and 
lifetime  QF( H) of such clusters and indicate in the corresponding 
domain of the phase diagram, where such phenomenon can be observed. The 
derived values  QF( H)  and  QF( H) allow us to reproduce qualitatively 
the available results for the quantum fluctuation contributions to the 
in-plane conductivity, magnetization, and the Nernst coefficient. 
Finally we predict the existence of a peak in the zero temperature 
transverse magneto-conductivity of layered superconductors at fields 
above Hc2(0).