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Title: Electronic structure and thermoelectric properties of p-type Ag-doped Mg₂Sn and Mg₂Sn{sub 1-x}Si{sub x} (x=0.05, 0.1)

An experimental and theoretical study of p-type Ag-doped Mg₂Sn and Mg₂Sn{sub 1-x}Si{sub x} (x=0.05, 0.1) is presented. Band structure calculations show that behavior of Ag in Mg₂Sn depends on the site it occupies. Based on Bloch spectral functions and density of states calculations, we show that if Ag substitutes for Sn, it is likely to form a resonant level; if it substitutes for Mg, a rigid-band-like behavior is observed. In both cases, the doped system should exhibit p-type conductivity. Experimentally, thermoelectric, thermomagnetic, and galvanomagnetic properties are investigated of p-type Mg₂Sn{sub 1–x}Si{sub x} (x=0, 0.05, 0.1) samples synthesized by a co-melting method in sealed crucibles. Ag effectively dopes the samples p-type, and thermoelectric power factors in excess of 20μW cm⁻¹K⁻² are observed in optimally doped samples. From the measured Seebeck coefficient, Nernst coefficient, and mobility, we find that the combination of acoustic phonon scattering, optical phonon scattering and defect scattering results in an energy-independent scattering rate. No resonant-like increase in thermopower is observed, which correlates well with electronic structure calculations assuming the location of Ag on Mg site.
Authors:
;  [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)
  2. (Poland)
  3. AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30-059 Krakow (Poland)
  4. (United States)
Publication Date:
OSTI Identifier:
22305825
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARRIER MOBILITY; CRYSTAL DEFECTS; DOPED MATERIALS; ELECTRONIC STRUCTURE; MAGNESIUM COMPOUNDS; MELTING; P-TYPE CONDUCTORS; SILICON COMPOUNDS; SILVER ADDITIONS; SPECTRAL FUNCTIONS; THERMOELECTRIC PROPERTIES; TIN COMPOUNDS