Effect of electron correlation on thermoelectric properties of the full-Heusler compound Fe$_2$VAl*

Heusler-type alloys have been studied extensively since they were first discovered by Heusler in 1903. Among those Fe$_2$VAl became interesting when Nishino {\it et. al.}[1] suggested that it might be a heavy fermion system. LDA/GGA calculations have shown that Fe$_2$VAl is a pseudo-gap system with sharp edges in the density of state near the Fermi level. This feature makes it a promising thermoelectric material. Since then electronic properties of nominally pure and doped Fe$_2$VAl have been studied extensively. However the exact nature of the ground state of this system is still not well understood. Since it contains d-electrons one expects electron correlation effects to be important. We have carried out band structure calculations using GGA+U method with several values of the on-site Coulomb interaction parameter U. Using the obtained band structure, transport coefficients were calculated within Boltzmann approach. Electronic structure and thermoelectric properties were studied for different values of U and compared to available experiments.\\[4pt] [1] Y. Nishino {\it et. al., Phys. Rev. Lett. {\bf 79} (10), 1909} (1997).