Thermoelectric transport properties of topological insulators
The thermoelectric power of materials is a measure of the voltage drop in a material sample
in response to a temperature gradient across the sample. Materials with high thermopower can be used as a device for efficient and clean conversion heat into electricity. The efficiency of a thermoelectric device is characterized by a parameter called the figure of merit ZT given by,
, where T is the temperature, σ is the electrical conductivity,
S is the Seebeck coefficient or thermopower and κ is the thermal conductivity. Large scale application of thermoelectric devices in harnessing heat energy has been hampered by its low figure of merit which depend upon the conflicting the transport coefficients. Typical value of
ZT for semiconductors is ~1. The main objective in the field of thermoelectric research has been to enhance the figure of merit.
A recent direction in the quest for high ZT materials has been the topological insulators (TI). It has been realized that the presence of heavy elements in TIs leads to low (phonon part of the thermal conductivity) which is required to obtain large ZT. The question arises that, does the the nontrivial topology of band structures also has any implication to the thermoelectric properties of these materials? Another interesting question is, can strong correlation physics coupled with lower in interacting topological insulators, such as , lead to a hight ZT? To address these questions, in this project we plan to study the thermoelectric transport properties of these materials using numerical methods such as the quantum Monte Carlo (QMC).
