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 language | English |
|---|---|
| Article number | 2314499 |
| Journal | Advanced Functional Materials |
| Volume | 34 |
| Issue number | 18 |
| DOIs | |
| State | Published - May 2 2024 |
Funding
J.D. and L.H. contributed equally to the work. This study was supported by the MOE ACRF Tier 1 RG128/21, RT6/22, the Basic Science Center Project of NSFC under Grant No. 52388201, the National Key R&D Program of China No. 2023YFB3809400, and NSFC under Grant No. 52073155 and No. 52150092. MGK acknowledges partial support from the U.S. Department of Energy, Office of Science Basic Energy Sciences under grant DE‐SC0024256, DOE Office of Science. This study also used the EPIC facility of Northwestern University's NUANCE Center, which received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS 2025633), the MRSEC program (NSF DMR‐1720139) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois. Research performed at the NOMAD beamlines at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, U.S. Department of Energy. L.H. is supported by the JSPS fellowship for the International Research Fellows (No. P19057) and the synchrotron radiation experiments were performed at the BL02B2 beamline of SPring‐8 with the approval of the Japan Synchrotron Radia‐tion Research Institute (JASRI) (Proposal Nos. 2021A1074). The authors would also like to acknowledge the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore, for use of their electron microscopy/X‐ray facilities.
| Funders | Funder number |
|---|---|
| Office of Basic Sciences | |
| Office of Science Basic Energy Sciences | DE‐SC0024256 |
| Scientific User Facilities Division | |
| Soft and Hybrid Nanotechnology Experimental | NSF DMR‐1720139, NSF ECCS 2025633 |
| U.S. Department of Energy | |
| W. M. Keck Foundation | |
| Office of Science | |
| Northwestern University | |
| Ministry of Education - Singapore | RT6/22, RG128/21 |
| Japan Society for the Promotion of Science | 2021A1074, P19057 |
| National Natural Science Foundation of China | 52388201 |
| National Key Research and Development Program of China | 2023YFB3809400, 52150092, 52073155 |
Keywords
- low lattice thermal conductivity
- neutron pair distribution function
- off-centering
- thermoelectric