Thermoelectric materials are solids which can generate electricity when a
temperature gradient is applied. By developing new such materials we may
thus be able to capture otherwise wasted heat. Since currently
60% of usable power world-wide escapes as waste heat this has the
potential provide considerable energy savings. In addition, through the reverse
process (Peltier cooling) thermoelectric materials have the potential to
provide high-efficiency localized cooling for many applications.
New Semiconductors for Thermoelectric Applications;
Vibrational and heat-transfer properties, and
emerging electronic behavior.
Some of the ongoing work in our laboratory includes studies aimed at providing a
better fundemental understanding of the atomic-scale thermal and vibrational
properties of such materials.
We are using NMR spectroscopy to study anharmonic vibrational behavior of
encapsulated ions, and the corresponding effect on the thermoelectric
properties. Modeling by ab initio methods also helps us to
understand the physical structure of substituted materials, and we
are studying thermoelectric, transport, and magnetic behavior of these
materials as well.
Some of this work has focused on
materials, with fullerene-type cages encapsulating rare earth
and alkaline earth ions. The encapsulated ions can contribute to glass-like
vibrational properties as well as enhanced magnetic
and superconducting behavior. In addition to these materials we are currently
studying a wide range of thermoelectrics and thermoelectric materials,
including skutterudites, chalcogenides such as Cu2Se and CuAgSe, and
We are also interested in electronic behavior in these and
related materials. This includes identifying signatures of charge carriers
as well as their local magnetic susceptibilies, using mostly NMR as a
primary tool to probe the atomic-scale behavior. Our interests include
identifying spin and orbital effects as well as new topological electronic
properties of these materials, based on fundamental physical interest in
these emerging properties as well as the potential for next-generation
Our work has also been focused on the magnetic and vibrational behavior of new
magnetic materials, including iron alumindes,
Heusler alloys, and a number of Rare-earth-based materials.
For example see our recent
work on Ni2MnIn-related magnetocaloric
and related work on Magnetic Shape Memory-type Alloys.
We are interested in elucidating the multiferroic properties of these materials, such
as the coupled structual-magnetic transformations in the Heusler alloys,
and in understanding the interplay of itinerant and localized magnetic
moments that underlies the magnetic properties of these materials.
Techniques include NMR spectroscopy, magnetic susceptibility, specific heat
and transport, thermopower, and ab initio computational
New Metallic Materials;
shape memory materials and new alloys for magnetocaloric applications