Heat capacity study on anharmonicity in Ae 8Ga 16Ge 30 (Ae = Sr and Ba)

Jingtao Xu; Jun Tang; Kazumi Sato; Yoichi Tanabe; Satoshi Heguri; Hitoshi Miyasaka; Masahiro Yamashita; Katsumi Tanigaki

doi:10.1007/s11664-011-1607-z

Heat capacity study on anharmonicity in Ae ₈Ga ₁₆Ge ₃₀ (Ae = Sr and Ba)

Jingtao Xu, Jun Tang, Kazumi Sato, Yoichi Tanabe, Satoshi Heguri, Hitoshi Miyasaka, Masahiro Yamashita, Katsumi Tanigaki

Research output: Contribution to journal › Article › peer-review

11 Citations (Scopus)

Abstract

The heat capacity of single-crystalline samples of Sr ₈Ga ₁₆Ge ₃₀ (SGG) and Ba ₈Ga ₁₆Ge ₃₀ (BGG) clathrates was measured to investigate the anharmonicity of the encapsulated atoms. At low temperatures, BGG can be well described by a standard Debye model, and the C _p/T ³ versus T plot can be fitted with two Einstein temperatures: θ _E1 = 42 K and θ _E2 = 74 K. On the other hand, SGG shows deviation from the Debye model. Moreover, neither the Einstein model nor the soft potential model (SPM) alone can fit the peak in the C _p/T ³ versus T plot, and the peak should be fitted by employing both models. Our results indicate that the effective electron mass is enhanced by the anharmonic phonons.

Original language	English
Pages (from-to)	879-883
Number of pages	5
Journal	Journal of Electronic Materials
Volume	40
Issue number	5
DOIs	https://doi.org/10.1007/s11664-011-1607-z
Publication status	Published - 2011 May

Keywords

Clathrates
heat capacity
soft potential model
thermoelectric

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Electrical and Electronic Engineering
Materials Chemistry

Access to Document

10.1007/s11664-011-1607-z

Cite this

@article{8c7a18b0a37c48cd8ddddb3aa4148737,

title = "Heat capacity study on anharmonicity in Ae 8Ga 16Ge 30 (Ae = Sr and Ba)",

abstract = "The heat capacity of single-crystalline samples of Sr 8Ga 16Ge 30 (SGG) and Ba 8Ga 16Ge 30 (BGG) clathrates was measured to investigate the anharmonicity of the encapsulated atoms. At low temperatures, BGG can be well described by a standard Debye model, and the C p/T 3 versus T plot can be fitted with two Einstein temperatures: θ E1 = 42 K and θ E2 = 74 K. On the other hand, SGG shows deviation from the Debye model. Moreover, neither the Einstein model nor the soft potential model (SPM) alone can fit the peak in the C p/T 3 versus T plot, and the peak should be fitted by employing both models. Our results indicate that the effective electron mass is enhanced by the anharmonic phonons.",

keywords = "Clathrates, heat capacity, soft potential model, thermoelectric",

author = "Jingtao Xu and Jun Tang and Kazumi Sato and Yoichi Tanabe and Satoshi Heguri and Hitoshi Miyasaka and Masahiro Yamashita and Katsumi Tanigaki",

note = "Funding Information: This work was supported by Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (Nos. 18204030, 19014001, 18651075, and 18204032). This work was carried out under KAKENHI (Grant-in-Aid for Scientific Research) on Priority Areas New Materials Science Using Regulated Nano Spaces-Strategy in Ubiquitous Elements from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. The present work is also partially supported by the Tohoku University GCOE Program Particle-Matter Hierarchy of MEXT, Japan.",

year = "2011",

month = may,

doi = "10.1007/s11664-011-1607-z",

language = "English",

volume = "40",

pages = "879--883",

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TY - JOUR

T1 - Heat capacity study on anharmonicity in Ae 8Ga 16Ge 30 (Ae = Sr and Ba)

AU - Xu, Jingtao

AU - Tang, Jun

AU - Sato, Kazumi

AU - Tanabe, Yoichi

AU - Heguri, Satoshi

AU - Miyasaka, Hitoshi

AU - Yamashita, Masahiro

AU - Tanigaki, Katsumi

N1 - Funding Information: This work was supported by Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (Nos. 18204030, 19014001, 18651075, and 18204032). This work was carried out under KAKENHI (Grant-in-Aid for Scientific Research) on Priority Areas New Materials Science Using Regulated Nano Spaces-Strategy in Ubiquitous Elements from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. The present work is also partially supported by the Tohoku University GCOE Program Particle-Matter Hierarchy of MEXT, Japan.

PY - 2011/5

Y1 - 2011/5

N2 - The heat capacity of single-crystalline samples of Sr 8Ga 16Ge 30 (SGG) and Ba 8Ga 16Ge 30 (BGG) clathrates was measured to investigate the anharmonicity of the encapsulated atoms. At low temperatures, BGG can be well described by a standard Debye model, and the C p/T 3 versus T plot can be fitted with two Einstein temperatures: θ E1 = 42 K and θ E2 = 74 K. On the other hand, SGG shows deviation from the Debye model. Moreover, neither the Einstein model nor the soft potential model (SPM) alone can fit the peak in the C p/T 3 versus T plot, and the peak should be fitted by employing both models. Our results indicate that the effective electron mass is enhanced by the anharmonic phonons.

AB - The heat capacity of single-crystalline samples of Sr 8Ga 16Ge 30 (SGG) and Ba 8Ga 16Ge 30 (BGG) clathrates was measured to investigate the anharmonicity of the encapsulated atoms. At low temperatures, BGG can be well described by a standard Debye model, and the C p/T 3 versus T plot can be fitted with two Einstein temperatures: θ E1 = 42 K and θ E2 = 74 K. On the other hand, SGG shows deviation from the Debye model. Moreover, neither the Einstein model nor the soft potential model (SPM) alone can fit the peak in the C p/T 3 versus T plot, and the peak should be fitted by employing both models. Our results indicate that the effective electron mass is enhanced by the anharmonic phonons.

KW - Clathrates

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KW - soft potential model

KW - thermoelectric

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