Condensed-Matter Physics & Materials Science Seminar

"Transport properties of novel thermoelectric materials"

Presented by Hang Chi, Department of Physics, University of Michigan

Thursday, May 28, 2015, 11:00 am — Bldg.480 Conf. Rm

Thermoelectric materials can recover waste industrial heat and convert it to electricity as well as provide efficient local cooling of electronic devices. The efficiency (determined by the dimensionless figure-of-merit ZT) of such environmentally responsible and exceptionally reliable solid state energy conversion can be enhanced through (i) electronic band engineering (n-type Mg2Si-Mg2Sn solid solutions and p-type SnTe) and (ii) thermal conductivity reduction (Ge/Te double substituted CoSb3). Detailed transport and structure studies of Bi2Te3-based single crystals demonstrate that a bulk (semi-)insulating state for such a topological insulator can be achieved via group III (Tl or In) elemental doping, which opens an avenue for further investigations of transport phenomena related to surface states. Further systematic study in Bi2Te3-based molecular beam epitaxial (MBE) thin films grown on sapphire (0001) and/or BaF2 (111) substrates, reveal that the peak of phonon drag can be tuned by the choice of substrates with different Debye temperatures.

Hosted by: Qiang Li

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