Date/Time Date(s) - 01/03/20063:30 pm - 4:30 pm
Title: A dual vortex lattice – from a phase fluctuating superconductor to a vibrating pair Wigner crystal
Speaker: Dr. Tami Pereg-Barnea
Institute: University of Texas
Location: ABB 102
Description:
The recent discovery of non-dispersing charge modulations in underdoped cuprate superconductors has been explained by the formation of a Cooper pair Wigner crystal [1]. The crystallization is a result of strong phase fluctuations and appear close to and at the pseudogap phase. In this talk I will review the scenario of phase fluctuations and relate it to various experimental results, including dispersing and non-dispersing modulations in the local density of states seen in STM. Specifically, it will be shown how phase fluctuations may lead to crystallization of pairs. This is done by a duality transformation to a condensed state of vortices. Based on this vortex-boson duality a theoretical picture is suggested to relate the charge modulations and the mysterious increase in the thermal conductivity [2] recently observed in the underdoped non-superconducting state of YBCO. This addition to the thermal conductivity has bosonic temperature dependence and is attributed within the model to the vibrational modes of the pair Wigner crystal.
[1] Z. Tesanovic, Phys. Rev. Lett. 93, 217004 (2004). [3] L. Taillefer (unpublished).