  The electronic and transport properties of the half-Heusler compound LaPtSb
are investigated by performing first-principles calculations combined with
semi-classical Boltzmann theory and deformation potential theory. Compared with
many typical half-Heusler compounds, the LaPtSb exhibits obviously larger power
factor at room temperature, especially for the n-type system. Together with the
very low lattice thermal conductivity, the thermoelectric figure of merit (ZT)
of LaPtSb can be optimized to a record high value of 2.2 by fine tuning the
carrier concentration.
