Metallic Ternary Telluride with Sphalerite Superstructure

Amit Adhikary, Sudip Mohapatra, Seng Huat Lee, Yew San Hor, Puja Adhikari, Wai Yim Ching, Amitava Choudhury

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.0521(11) Å, c = 9.568(2) Å, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 105 S m-1 at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 1021 cm-3 and Hall mobility of 4.5 cm2 V-1 s-1 at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m-1 K-1 at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼0.5 eV can be obtained.

Original languageEnglish (US)
Pages (from-to)2114-2122
Number of pages9
JournalInorganic chemistry
Volume55
Issue number5
DOIs
StatePublished - Mar 7 2016

Fingerprint

Hall mobility
tellurides
Seebeck coefficient
zincblende
Charge carriers
Band structure
Adamantane
Seebeck effect
charge carriers
Hall effect
Fermi level
Carrier concentration
Thermal conductivity
conductivity
Energy gap
electronics
figure of merit
Atoms
thermal conductivity
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Adhikary, A., Mohapatra, S., Lee, S. H., Hor, Y. S., Adhikari, P., Ching, W. Y., & Choudhury, A. (2016). Metallic Ternary Telluride with Sphalerite Superstructure. Inorganic chemistry, 55(5), 2114-2122. https://doi.org/10.1021/acs.inorgchem.5b02516
Adhikary, Amit ; Mohapatra, Sudip ; Lee, Seng Huat ; Hor, Yew San ; Adhikari, Puja ; Ching, Wai Yim ; Choudhury, Amitava. / Metallic Ternary Telluride with Sphalerite Superstructure. In: Inorganic chemistry. 2016 ; Vol. 55, No. 5. pp. 2114-2122.
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abstract = "A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) {\AA}, b = 6.0521(11) {\AA}, c = 9.568(2) {\AA}, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 105 S m-1 at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 1021 cm-3 and Hall mobility of 4.5 cm2 V-1 s-1 at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m-1 K-1 at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼0.5 eV can be obtained.",
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Adhikary, A, Mohapatra, S, Lee, SH, Hor, YS, Adhikari, P, Ching, WY & Choudhury, A 2016, 'Metallic Ternary Telluride with Sphalerite Superstructure', Inorganic chemistry, vol. 55, no. 5, pp. 2114-2122. https://doi.org/10.1021/acs.inorgchem.5b02516

Metallic Ternary Telluride with Sphalerite Superstructure. / Adhikary, Amit; Mohapatra, Sudip; Lee, Seng Huat; Hor, Yew San; Adhikari, Puja; Ching, Wai Yim; Choudhury, Amitava.

In: Inorganic chemistry, Vol. 55, No. 5, 07.03.2016, p. 2114-2122.

Research output: Contribution to journalArticle

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AU - Adhikary, Amit

AU - Mohapatra, Sudip

AU - Lee, Seng Huat

AU - Hor, Yew San

AU - Adhikari, Puja

AU - Ching, Wai Yim

AU - Choudhury, Amitava

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N2 - A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.0521(11) Å, c = 9.568(2) Å, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 105 S m-1 at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 1021 cm-3 and Hall mobility of 4.5 cm2 V-1 s-1 at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m-1 K-1 at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼0.5 eV can be obtained.

AB - A new ternary compound with composition Cu5Sn2Te7 has been synthesized using the stoichiometric reaction of Cu, Sn, and Te. The compound crystallizes in C2 space group with unit cell parameters of a = 13.549(2) Å, b = 6.0521(11) Å, c = 9.568(2) Å, and β = 98.121(2)°. Cu5Sn2Te7 is a superstructure of sphalerite and exhibits tetrahedral coordination of Cu, Sn, and Te atoms, containing a unique adamantane-like arrangement. The compound is formally mixed valent with a high electrical conductivity of 9.8 × 105 S m-1 at 300 K and exhibits metallic behavior having p-type charge carriers as indicated from the positive Seebeck coefficient. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 × 1021 cm-3 and Hall mobility of 4.5 cm2 V-1 s-1 at 300 K. The electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. Band structure analysis suggests that the effective mass of the hole state is small and could be responsible for high electronic conductivity and Hall mobility. The high thermal conductivity of 15.1 W m-1 K-1 at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit (ZT) for this compound. Theoretical calculations indicate that if Cu5Sn2Te7 is turned into a valence precise compound by substituting one Cu by a Zn, a semiconducting material, Cu4ZnSn2Te7, with a direct band gap of ∼0.5 eV can be obtained.

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Adhikary A, Mohapatra S, Lee SH, Hor YS, Adhikari P, Ching WY et al. Metallic Ternary Telluride with Sphalerite Superstructure. Inorganic chemistry. 2016 Mar 7;55(5):2114-2122. https://doi.org/10.1021/acs.inorgchem.5b02516