Superfluid stiffness renormalization and critical temperature enhancement in a composite superconductor
Seminar
Speaker
Prof. Dror Orgad, Hebrew University
Date
12/12/2013 - 15:30 - 14:30Add to Calendar
2013-12-12 14:30:00
2013-12-12 15:30:00
Superfluid stiffness renormalization and critical temperature enhancement in a composite superconductor
Increasing superconductors' critical temperature has been a long standing goal in material science.
In order to do so, both a high Cooper pairing energy and a large phase coherence of the pairs are required.
Unfortunately, systems in which pairing is strong typically do not exhibit a correspondingly high transition
temperature due to their susceptibility to large phase fluctuations. Conversely, large phase stiffness is a
property of all simple metals, but these typically have (at best) weak pairing. It has been suggested that it
is possible to overcome this tension by coupling a superconductor to a metallic layer. We consider a model
of such a composite system, and determine its critical temperature using a combination of analytic and
Monte Carlo methods. We find that the maximal critical temperature is bounded from above when the pairing
is strong, and scales like a fraction of the zero temperature pairing gap when the pairing is weak. In this
weak pairing regime the critical temperature seems to exceed that of a homogeneous model of
the same pairing energy.
Seminar room 210, Reznick, bld 209
המחלקה לפיזיקה
physics.dept@mail.biu.ac.il
Asia/Jerusalem
public
Place
Seminar room 210, Reznick, bld 209
Abstract
Increasing superconductors' critical temperature has been a long standing goal in material science.
In order to do so, both a high Cooper pairing energy and a large phase coherence of the pairs are required.
Unfortunately, systems in which pairing is strong typically do not exhibit a correspondingly high transition
temperature due to their susceptibility to large phase fluctuations. Conversely, large phase stiffness is a
property of all simple metals, but these typically have (at best) weak pairing. It has been suggested that it
is possible to overcome this tension by coupling a superconductor to a metallic layer. We consider a model
of such a composite system, and determine its critical temperature using a combination of analytic and
Monte Carlo methods. We find that the maximal critical temperature is bounded from above when the pairing
is strong, and scales like a fraction of the zero temperature pairing gap when the pairing is weak. In this
weak pairing regime the critical temperature seems to exceed that of a homogeneous model of
the same pairing energy.
תאריך עדכון אחרון : 05/12/2022
