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Title: Enhanced thermoelectric performance driven by high-temperature phase transition in the phase change material Ge4SbTe5

Phase change materials are identified for their ability to rapidly alternate between amorphous and crystalline phases and have large contrast in the optical/electrical properties of the respective phases. The materials are primarily used in memory storage applications, but recently they have also been identified as potential thermoelectric materials. Many of the phase change materials researched today can be found on the pseudo-binary (GeTe)1-x(Sb2Te3)x tie-line. While many compounds on this tie-line have been recognized as thermoelectric materials, here we focus on Ge4SbTe5, a single phase compound just off of the (GeTe)1-x(Sb2Te3)x tie-line, that forms in a stable rocksalt crystal structure at room temperature. We find that stoichiometric and undoped Ge4SbTe5 exhibits a thermal conductivity of ~1.2 W/m-K at high temperature and a large Seebeck coefficient of ~250 μV/K. The resistivity decreases dramatically at 623 K due to a structural phase transition which lends to a large enhancement in both thermoelectric power factor and thermoelectric figure of merit at 823 K. In a more general sense the research presents evidence that phase change materials can potentially provide a new route to highly efficient thermoelectric materials for power generation at high temperature.
 [1] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Michigan State Univ., East Lansing, MI (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Materials Research
Additional Journal Information:
Journal Volume: 30; Journal Issue: 17; Journal ID: ISSN 0884-2914
Materials Research Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
36 MATERIALS SCIENCE; thermoelectric; phase transformation; semiconducting
OSTI Identifier: