Glasslike excitations in single crystalline Sr8Ga16Ge30 clathrates

V. Keppens; M. A. McGuire; A. Teklu; C. Laermans; B. C. Sales; D. Mandrus; B. C. Chakoumakos

doi:10.1016/S0921-4526(02)00431-3

Glasslike excitations in single crystalline Sr₈Ga₁₆Ge₃₀ clathrates

V. Keppens, M. A. McGuire, A. Teklu, C. Laermans, B. C. Sales, D. Mandrus, B. C. Chakoumakos

Single Crystal Diffraction

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

28 Scopus citations

Abstract

Low-temperature ultrasonic attenuation and resonant ultrasound spectroscopy (RUS) data are reported on single crystals of the semiconductor Sr₈Ga₁₆Ge₃₀. The attenuation shows a strikingly glasslike behavior, implying that the elastic properties of the clathrate crystal at low temperatures (T<1K) are dominated by the presence of tunneling states. At slightly higher temperatures, the RUS data reflect the presence of a 2-level system with an energy-spacing of 45K. The origin of these low-energy excitations is found in the 'rattling' Sr-atom, which occupies a fourfold split site in the clathrate structure.

Original language	English
Pages (from-to)	95-100
Number of pages	6
Journal	Physica B: Physics of Condensed Matter
Volume	316-317
DOIs	https://doi.org/10.1016/S0921-4526(02)00431-3
State	Published - May 2002

Funding

This work is supported in part by ONR. Oak Ridge National Laboratory is managed by UT-Batelle, LLC, for the US Department of Energy under Contract No. DE-AC05-00OR22725.

Funders	Funder number
UT-Batelle
Office of Naval Research
U.S. Department of Energy	DE-AC05-00OR22725

Keywords

Clathrates
Elastic properties
Tunneling states

Access to Document

10.1016/S0921-4526(02)00431-3

Cite this

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title = "Glasslike excitations in single crystalline Sr8Ga16Ge30 clathrates",

abstract = "Low-temperature ultrasonic attenuation and resonant ultrasound spectroscopy (RUS) data are reported on single crystals of the semiconductor Sr8Ga16Ge30. The attenuation shows a strikingly glasslike behavior, implying that the elastic properties of the clathrate crystal at low temperatures (T<1K) are dominated by the presence of tunneling states. At slightly higher temperatures, the RUS data reflect the presence of a 2-level system with an energy-spacing of 45K. The origin of these low-energy excitations is found in the 'rattling' Sr-atom, which occupies a fourfold split site in the clathrate structure.",

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T1 - Glasslike excitations in single crystalline Sr8Ga16Ge30 clathrates

AU - Keppens, V.

AU - McGuire, M. A.

AU - Teklu, A.

AU - Laermans, C.

AU - Sales, B. C.

AU - Mandrus, D.

AU - Chakoumakos, B. C.

PY - 2002/5

Y1 - 2002/5

N2 - Low-temperature ultrasonic attenuation and resonant ultrasound spectroscopy (RUS) data are reported on single crystals of the semiconductor Sr8Ga16Ge30. The attenuation shows a strikingly glasslike behavior, implying that the elastic properties of the clathrate crystal at low temperatures (T<1K) are dominated by the presence of tunneling states. At slightly higher temperatures, the RUS data reflect the presence of a 2-level system with an energy-spacing of 45K. The origin of these low-energy excitations is found in the 'rattling' Sr-atom, which occupies a fourfold split site in the clathrate structure.

AB - Low-temperature ultrasonic attenuation and resonant ultrasound spectroscopy (RUS) data are reported on single crystals of the semiconductor Sr8Ga16Ge30. The attenuation shows a strikingly glasslike behavior, implying that the elastic properties of the clathrate crystal at low temperatures (T<1K) are dominated by the presence of tunneling states. At slightly higher temperatures, the RUS data reflect the presence of a 2-level system with an energy-spacing of 45K. The origin of these low-energy excitations is found in the 'rattling' Sr-atom, which occupies a fourfold split site in the clathrate structure.

KW - Clathrates

KW - Elastic properties

KW - Tunneling states

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