Joseph Orenstein (SIMES Friday Seminar)

Date(s) - Feb 21 2014
11:00 AM - 12:30 PM

Shasta Room, Bldg. 40, Room 361


 Quasiparticle recombination, collective modes, and competing order in cuprate superconductors

Joe Orenstein

UC Berkeley and LBNL

 In this talk I will present experimental results on time-resolved optical spectroscopy in cuprate superconductors.  By way of introduction, I will briefly describe how the recent confirmation of a universal charge density wave (CDW) state in the cuprates using X-ray diffraction has re-invigorated this 25 year old field.  I will then show that time-domain coherent optical spectroscopy provides important information regarding the overall phase diagram of the cuprates, present our initial observation of the amplitude mode of the CDW, and describe evidence for its dynamic competition with the superconducting state itself.  I will focus on two model cuprate systems: Hg-1201 and YBCO Ortho II, III, and VIII.  The first system presents the simplest possible cuprate structure, with individual CuO2 planes and perfect tetragonal (square) symmetry.  The latter is the system in which the clearest structural determinations of the CDW have been made.