Off-Centering of Ge Atoms in GeBi2Te4 and Impact on Thermoelectric Performance

Jinfeng Dong, Lei Hu, Jue Liu, Yukun Liu, Yilin Jiang, Zhiling Yu, Xian Yi Tan, Ady Suwardi, Qiang Zheng, Qian Li, Jing Feng Li, Vinayak P. Dravid, Qingyu Yan*, Mercouri G. Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The crystal structure and transport properties of GeBi2Te4 are investigated as a layered compound with potential applications as thermoelectric materials. A disordered arrangement of Ge and Bi atoms in a septuple-layer structure is discovered through synchrotron radiation X-ray diffraction and transmission electron microscopy. Neutron pair distribution function analysis revealed the presence of discordant Ge atoms with an off-centering distance of 0.12 Å at 300 K. The thermal conductivity of GeBi2Te4 is very low due to the strong phonon scattering. This is a result of the three Einstein local oscillators coupled with the disordered arrangement of atoms. This study also explores further the structural characteristics of these materials and their associated phonon scattering processes. The effect of Sb substitution for Ge on the electrical transport properties of the sample is profound, resulting in a change from p-type to n-type conduction. An enhanced thermoelectric figure of merit (ZT) of 0.45 at 523 K in the in-plane direction is obtained. This research provides valuable insights into the crystal structure and transport properties of GeBi2Te4, showcasing its promising role as a thermoelectric material with potential for near-room-temperature applications.

Original languageEnglish (US)
Article number2314499
JournalAdvanced Functional Materials
Volume34
Issue number18
DOIs
StatePublished - May 2 2024

Keywords

  • low lattice thermal conductivity
  • neutron pair distribution function
  • off-centering
  • thermoelectric

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Biomaterials
  • General Materials Science
  • Condensed Matter Physics
  • Electrochemistry

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