Electronic Structure and Charge Dynamics of Huesler Alloy Fe2TiSn Probed   by Infrared and Optical Spectroscopy
  We report on the electrodynamics of a Heusler alloy Fe2TiSn probed over four decades in energy: from the far infrared to the ultraviolet. Our results do not support the suggestion of Kondo-lattice behavior inferred from specific heat measurements. Instead, we find a conventional Drude-like response of free carriers, with two additional absorption bands centered at around 0.1 and 0.87 eV. The latter feature can be interpreted as excitations across a pseudogap, in accord with band structure calculations. 
S.V.Dordevic, D.N.Basov, A.Slebarski, M.B.Maple and L.Degiorgi