University of Minnesota
School of Physics & Astronomy

Condensed Matter Seminar

Thursday, February 12th 2009
1:25 pm:
Condensed Matter Seminar in 210 Physics
Speaker: Dr. Minhyea Lee, National Insitute of Standards and Technology
Subject: Large Thermopower and Strong Correlation in Sodium Cobalt Oxides
Minhyea Lee is a candidate for the Cond. Matter Experimentalist Asst. Prof. position.

Electronic properties in strongly correlated systems often reveal strikingly enhanced features compared with those in conventional materials. Examples are the high transition temperature in cuprate superconductors and the colossal magnetoresistance in manganites. The layered triangular lattice cobaltates Na_x CoO_2 exhibit several interesting electronic phases such as superconductivity, charge ordering and high thermopower, as the Na content is varied. In this talk I will describe our experimental progress in the high Na doping range characterized by even steeper enhancement of thermopower, which makes this material a strong candidate for low temperature thermoelectric applications. Tim permitting, I will present recent data showing dramatic changes in transport upon very small variations in Na content, and discuss these findings in relation to a recent discovery of periodic Na ordering.

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