Transport and optical properties of the gapless Heusler compound PtYSb

This work presents a systematic study on the optical and transport properties of the Heusler compound PtYSb. The optical properties were investigated in a wide spectral range from 10 meV to 6.5 eV and compared to ab-initio calculations. For photon energies below 2.5 eV, the optical absorption increases linearly with photon energy. This is related with the conical shape of the electronic structure in the vicinity of the Fermi energy. The optical spectra reveal a maximum band gap of about 60 meV. Furthermore, the temperature dependence of thermal conductivity, electrical resistivity, Seebeck coefficient and Hall mobility were investigated. PtYSb exhibits very good thermoelectric properties with a high figure of merit ZT of 0.2 and a Hall mobility μh of 300 cm2/Vs at 350 K, which is the highest value obtained for Heusler compounds up to now. The carrier concentration ranges from 5 × 1018 at low temperature to 1019 cm−3 at 400 K.

[1]  Shuang Jia,et al.  Half-Heusler ternary compounds as new multifunctional experimental platforms for topological quantum phenomena. , 2010, Nature materials.

[2]  Wenguang Zhu,et al.  Half-Heusler compounds as a new class of three-dimensional topological insulators. , 2010, Physical review letters.

[3]  R. Cava,et al.  A new platform for topological quantum phenomena : Topological Insulator states in thermoelectric Heusler-related ternary compounds , 2010, 1003.0155.

[4]  M. A. Kouacou,et al.  Crossover from semiconductor to magnetic metal in semi-Heusler phases as a function of valence electron concentration , 1998 .

[5]  Bin Xu,et al.  Optical properties of the intermetallic compound Fe2TiSn , 2008 .

[6]  W. Jeitschko,et al.  Equiatomic Rare Earth ( Ln) Transition Metal Antimonides LnTSb ( T=Rh, lr) and Bismuthides LnTBi ( T=Rh, Ni, Pd, Pt) , 2002 .

[7]  Y. Grin,et al.  Magnetic, transport, and thermal properties of the half-Heusler compounds ErPdSb and YPdSb , 2007 .

[8]  Y. Bando,et al.  Large thermoelectric power in several metallic compounds of cerium and uranium , 2000 .

[9]  Claudia Felser,et al.  Tunable multifunctional topological insulators in ternary Heusler compounds. , 2010, Nature materials.

[10]  Claudia Felser,et al.  Electronic structure of Pt based topological Heusler compounds with C1b structure and zero band gap , 2011 .

[11]  Y. Grin,et al.  Magnetic and transport properties of rare-earth-based half-Heusler phases RPdBi: Prospective systems for topological quantum phenomena , 2011, 1106.3763.

[12]  Y. Bando,et al.  Thermoelectric and transport properties of CeBiPt and LaBiPt , 2001 .

[13]  Kimura,et al.  Pseudogap formation in the intermetallic compounds (Fe1-xVx)3Al , 2000, Physical review letters.

[14]  Z. Fisk,et al.  Magnetism and heavy fermion-like behavior in the RBiPt series , 1991 .

[15]  Su-Yang Xu,et al.  Topological electronic structure in half-Heusler topological insulators , 2010 .

[16]  R. Cava,et al.  Observation of a large-gap topological-insulator class with a single Dirac cone on the surface , 2009 .

[17]  H. Eckert,et al.  Defects in half-Heusler type antimonides ScTSb (T = Ni, Pd, Pt) , 2009 .

[18]  T. Takabatake,et al.  Thermodynamic and transport properties of the non-centrosymmetric superconductor LaBiPt , 2008 .

[19]  S. Malik,et al.  Magnetic behaviour of RPdSb (R = rare earth) compounds , 1991 .

[20]  E. Bucher,et al.  Thermoelectrical properties of the compounds ScMVIIISb and YMVIIISb (MVIII = Ni, Pd, Pt) , 2003 .