skip to main content

Title: Thermoelectric properties optimization of Fe{sub 2}VGa by tuning electronic density of states via titanium doping

We report the correlation between thermoelectric properties and electronic band structure of thermoelectric Heusler alloy Fe{sub 2}V{sub 1-x}Ti{sub x}Ga by comparing experimental measurements with theoretical calculations. The electrical resistivity data show that the semiconducting-like behavior of pure Fe{sub 2}VGa is transformed to a more metallic-like behavior at x = 0.1. Meanwhile, an enhancement of the Seebeck coefficient was observed for all Ti doped specimens at elevated temperatures with a peak value of 57 μV/K for x = 0.05 at 300 K. The experimental results can be elucidated by the calculated band structure, i.e., a gradual shifting of the Fermi level from the middle of the pseudogap to the region of valence bands. With optimized doping, the thermoelectric power factor can be significantly enhanced to 3.95 mW m{sup −1} K{sup −2} at room temperature, which is comparable to the power factors of Bi{sub 2}Te{sub 3}-based compounds. The synergy of thermal conductivity reduction due to the alloying effect and the significant increase of the thermoelectric power factor leads to higher order zT values than that of prime Fe{sub 2}VGa.
Authors:
 [1] ; ;  [1] ;  [2] ;  [3] ;  [3] ;  [2]
  1. Institute of Physics, Academia Sinica, 11529 Taipei, Taiwan (China)
  2. (China)
  3. Department of Physics, National Taiwan University, 10617 Taipei, Taiwan (China)
Publication Date:
OSTI Identifier:
22492867
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH TELLURIDES; DENSITY OF STATES; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; FERMI LEVEL; HEUSLER ALLOYS; POWER FACTOR; TEMPERATURE RANGE 0273-0400 K; THERMAL CONDUCTIVITY; THERMOELECTRIC PROPERTIES; TITANIUM