Collective-Goldstone-mode-induced ultralow lattice thermal conductivity in Sn-filled skutterudite
- Jilin Univ., Changchun (China). State Key Lab. of Superhard Materials, Key Lab. of Automobile Materials of MOE, and College of Materials Science and Engineering; Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
- Jilin Univ., Changchun (China). State Key Lab. of Superhard Materials, Key Lab. of Automobile Materials of MOE, and College of Materials Science and Engineering
- Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
Here, we demonstrate that the concept of Goldstone bosons can be exploited for phonon control and thermal conductivity reduction of materials. By studying lattice dynamics of the Sn filled skutterudite SnFe4Sb12, we find Sn off-centers in its coordination cage in contrast to the common rare earth fillers. This leads to low-frequency Goldstone-like modes below 1 THz associated mainly with Sn motions. Importantly, these involve collective motion of other atoms, especially Sb, in the host skutterudite lattice. The optical modes transversing to the Sn off-centering direction are identified as Goldstone type modes in association with a three-dimensional Mexican-hat-like potential energy surface. The interaction of these collective Goldstone modes with the host heat-carrying phonons is shown to lead to ultralow lattice thermal conductivity.
- Research Organization:
- Univ. of Missouri, Columbia, MO (United States); Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0001299; FG02-09ER46577
- OSTI ID:
- 1415615
- Alternate ID(s):
- OSTI ID: 1415534
- Journal Information:
- Physical Review B, Vol. 97, Issue 2; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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