CM-AMO Seminar | Bulk Semiconductors for Thermoelectric Energy Conversion and Spintronics, Speaker: Ferdinand Poudeu (UM MSE)
Tuesday, November 8, 2011
335 West Hall
Speaker: Ferdinand Poudeu (UM MSE)Designing thermoelectric materials with large figure of merit (ZT) has proven extremely difficult over the past six decades, despite breakthroughs concerning lattice thermal conductivity reduction using nanostructuring or enhancements in the Seebeck coefficient through distortion of electronic density of states, because of the interdependence between electronic and thermal transport properties. Recently, we have developed innovative approaches to drastically increase the figure of merit of half-Heusler based materials through simultaneous large enhancement of the power factor and drastic reduction in the thermal conductivity. Our strategy is focused on atomic-scale structural engineering of the semiconducting half-Heusler matrix through the confinement of metallic full-Heusler inclusion phases on the lattice constant length-scale. In this lecture, I will discuss some of our recent findings in the n-type Zr0.25Hf0.75Ni1+xSn1-yPny (Pn = Sb, Bi) nanocomposites. In addition, our group is also actively involved in the development of new high Curie temperature ferromagnetic semiconductors based on transition metal chalcogenides, for potential application in spintronics. I will discuss some of our recent results in the (Fe,Mn)/Pb/(Sb,Bi)/Se systems. Emphasis will be placed on structure – composition – property relationships in the MxPb4-xSb4Se10 and MPn2-ySnySe4 (M = Mn, Fe; Pn = Sb, Bi) phases.