88th Annual Meeting of the Southeastern Section of the APS
Volume 66, Number 16
Thursday–Saturday, November 18–20, 2021;
University Center Club, Florida State University, Tallahassee, Florida
Session M05: Thermoelectrics/Superconductivity
2:00 PM–3:48 PM,
Friday, November 19, 2021
Room: West Ballroom
Chair: Ryan Baumbach, NHMFL
Abstract: M05.00001 : Quantum Materials Research for Energy Conversion Applications*
2:00 PM–2:30 PM
Preview Abstract
Abstract
Author:
Kaya Wei
(Florida State University)
The search for clean and renewable energy production methods is directly
related to discovery of novel materials and composites with desired
structural and electronic properties. Thermoelectric devices, which allow
for direct energy conversion between heat and electricity, have a unique
place in this effort since they enable solid state schemes for power
generation and refrigeration/heating, involve no harmful gasses/liquids,
avoid energy losses and wear/tear from mechanically moving parts, and take
advantage of naturally occurring temperature gradients. These
characteristics make them ideal for applications including electricity
generation in extreme and remote environments. In order to efficiently
convert energy using thermoelectricity, several optimized properties are
required. These include a high electrical conductivity $\sigma $, a large
Seebeck coefficient $S$, and a low thermal conductivity $\kappa $. Together,
these quantities define the dimensionless thermoelectric figure of merit,
\textit{ZT} $= \quad S^{2}\sigma T$/$\kappa $, where $T$ is the absolute temperature. Larger
\textit{ZT} values directly correspond to more efficient thermoelectric devices and
there are no known fundamental limitations on how large \textit{ZT }can be. Although all
electrical conductors exhibit a thermoelectric effect, their efficacy is
limited by a fundamental proportionality between electrical conductivity and
the electronic component of the thermal conductivity. In this talk I will
report several approaches that have been undertaken in the search for new
quantum materials for potential energy conversion applications. For example,
a prevailing strategy to overcome the competition between electrical and
thermal conductance is to produce materials with large and cage-like unit
cells where phonons are strongly scattered but electrons move easily.
Following this strategy, we recently investigated the heavy-fermion
compounds Yb\textit{TM}$_{2}$Zn$_{20}$ (\textit{TM} $=$ Co, Rh, Ir) and showed that they exhibit
competitively high power factors in addition to large \textit{ZT} values at 35 K. Our
latest results indicate that compositional modifications contribute to
further enhanced thermoelectric properties.
*The National High Magnetic Field Laboratory is supported by National Science Foundation through NSF/DMR-1644779 and the State of Florida.