Condensed Matter Physics Seminar

A 'checkerboard' electronic crystal state in lightly hole-doped Na-CCOC

Dr. Christian Lupien
Cornell University
Tuesday, October 12, 2004
Higgins 235, 2pm

After more than 15 years of intense study, the high-T_c superconductors are still not well understood. One reason is that the normal state, from which superconductivity arise, is unusual especially for the so called underdoped materials. It derives from a doped Mott insulator and shows a pseudogap behavior. I will present scanning tunneling microscopy and spectroscopy (STM/STS) taken at very low temperature on a highly underdoped member of the high-T_c family, the oxychloride Ca_2-xNa_xCuO₂Cl₂ (Na-CCOC). At the low doping studied the samples are around the insulator/superconductor transition. After introducing Na-CCOC and the measurement technique I will show our recent data that reveals a strong reorganization of the electronic structure at the atomic scale and its relation to the pseudogap state and other STM/STS studies of high-T_c materials.