Joseph Heremans

OES and Professor - MAE and Physics

Dr. Heremans' research is focused on thermal transport properties of solids and nanostructures, aimed at developing thermoelectric materials with improved efficiency for both electrical power generation and heat pumping applications. A decade of research in his group and others has led to improved efficiencies through a reduction of the thermal conductivity by adding nanostructrues to thermoelectric materials. In contrast, since 2005, he has focused on developing bulk thermoelectric materials in which the increased efficiency is based on the details of the chemical bonds at sub-nanometer levels. One approach maximizes the anharmonicity of the bonds between atoms to reduce the thermal conductivity, and is published in Phys. Rev. Lett. 101, 035901 (2008). A second approach increases the thermoelectric power by using a resonance between the electronic states of Tl atoms and the valence band of PbTe (Science 321 554, 2008).  In 2010, TML reported the first measurement of the spin-Seebeck effect on a semiconductor, in collaboration with Prof. Roberto Myers' group (Nature Materials, 9, 898 (2010)).  This effect is a change in spin-polarisation in a temperature gradient.  In Phys. Rev. Lett. 106, 186601 (2011) the link was established between the spin-Seebeck effect and the interaction between phonons and "magnons", perturbations of the magnetisation in ferromagnets.  These measurements promise to open a new avenue in thermodynamics, called spin-caloritronics: like thermoelectrics converts heat into electricity, spin-caloritronics promises to convert heat into magetism.

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614 247-8869
E443 Scott Laboratory
201 W. 19th Ave
Columbus, Oh 43210