Anomalous electronic properties in layered, disordered ZnVSb

Bensen, Erik A.; Ciesielski, Kamil; Gomes, Lídia C.; Ortiz, Brenden R.; Falke, J.; Pavlosiuk, Orest; Weber, Daniel; Braden, Tara; Steirer, K. Xerxes; Szymański, Damian; Goldberger, Joshua E.; Kuo, Chang Yang; Chen, Chien Te; Chang, C. F.; Tjeng, L. H.; Kaczorowski, D.; Ertekin, Elif; Toberer, Eric S.

doi:10.1103/physrevmaterials.5.015002

Cited by 4 publications

(8 citation statements)

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“…The theoretical C p was calculated accordingly to the procedure described in Ref. 59 In 2-300 K range the so-obtained theoretical and experimental C p 's are in good agreement for all three compounds (Fig. S13a, d, g).…”

Section: Heat Capacitymentioning

confidence: 55%

“…60,61 The eventual values of U were chosen based on comparison of theoretical density of states with experimental X-ray photoemission spectroscopy results. 59 No significant impact of exchange-correlation potential on the phonon dispersion was observed for the type-I and type-XI clathrates. For the tunnel compound, however, such correction significantly reduced the number of negative modes.…”

Section: Theoretical Methodsmentioning

confidence: 94%

“…This value was chosen using our previous work for a zinc antimonide ZnVSb. 59 There, we checked the typical range of the parameter U for Zn in the +5, +6, +7 eV. 60,61 The eventual values of U were chosen based on comparison of theoretical density of states with experimental X-ray photoemission spectroscopy results.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…THz. These frequencies are obtained by solving for the Einstein temperatures Θ E , with the conversion Θ E ≈ 5T max 59 and ν E1 = k B Θ E1 /h. The lower frequency corresponds to the 'ladder' in phonon dispersion created by K rattling modes in frequency range 0.17-0.70 THz (cf., Fig.…”

Section: Heat Capacitymentioning

confidence: 99%

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Origin of ultra-low thermal conductivity in unconventional clathrates: Strong scattering from extremely low-frequency rattling modes

Ciesielski¹,

Ortiz²,

Gomes³

et al. 2023

Preprint

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Section: Heat Capacitymentioning

confidence: 55%

Section: Theoretical Methodsmentioning

confidence: 94%

Section: Theoretical Methodsmentioning

confidence: 99%

Section: Heat Capacitymentioning

confidence: 99%

See 2 more Smart Citations

Origin of ultra-low thermal conductivity in unconventional clathrates: Strong scattering from extremely low-frequency rattling modes

Ciesielski¹,

Ortiz²,

Gomes³

et al. 2023

Preprint

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“…This value was chosen using our previous work for the zinc antimonide ZnVSb . There, we checked the typical range of the parameter U for Zn at +5, +6, and +7 eV. , The eventual values of U were chosen on the basis of a comparison of theoretical density of states with experimental X-ray photoemission spectroscopy results . No significant impact of the exchange-correlation potential on the phonon dispersion was observed for the type-I and type-XI clathrates.…”

Section: Methodsmentioning

confidence: 99%

Strong Scattering from Low-Frequency Rattling Modes Results in Low Thermal Conductivity in Antimonide Clathrate Compounds

et al. 2023

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Recent discoveries of materials with ultralow thermal conductivity open a pathway to significant developments in the field of thermoelectricity. Here, we conduct a comparative study of three chemically similar antimonides to establish the root causes of their extraordinarily low thermal conductivity (0.4–0.6 W m–1 K–1 at 525 K). The materials of interest are the unconventional type-XI clathrate K58Zn122Sb207, the tunnel compound K6.9Zn21Sb16, and the type-I clathrate K8Zn15.5Cu2.5Sb28 discovered herein. Calculations of the phonon dispersions show that the type-XI compound exhibits localized (i.e., rattling) phonon modes with unusually low frequencies that span the entire acoustic regime. In contrast, rattling in type I clathrate is observed only at higher frequencies, and no rattling modes are present in the tunnel structure. Modeling reveals that low-frequency rattling modes profoundly limit the acoustic scattering time; the scattering time of the type-XI clathrate is half that of the type-I clathrate and a quarter of that of the tunnel compound. For all three materials, the thermal conductivities are additionally suppressed by soft framework bonding that lowers the acoustic group velocities and structural complexity that leads to diffusonic character of the optical modes. Understanding the details of thermal transport in structurally complex materials will be crucial for developing the next generation of thermoelectrics.

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