CPM Seminar

Probing the electronic order of a high-T_c superconductor with low temperature STM

Christian Lupien

Université de Sherbrooke

After almost 20 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 data that reveals a strong reorganization of the electronic structure at the atomic scale. I will also show more recent data that tries to `map the mottness'.