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Volumn 45, Issue 4, 2006, Pages 599-602

Unusual lone pairs in tellurium and their relevance for superconductivity

Author keywords

Ab initio calculations; ELF (Electron Localization Function); High pressure chemistry; Superconductivity; Tellurium

Indexed keywords

BAND STRUCTURE; HIGH PRESSURE EFFECTS; SUPERCONDUCTIVITY; THERMAL EFFECTS;

EID: 31044436404     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200502673     Document Type: Article
Times cited : (26)

References (63)
  • 21
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    • [10a,b] The values are 10.00, 10.46, and 8.57 eV for sulfur (n = 3), selenium (n = 4), and tellurium (n = 5), respectively, a) J. F. Janak, V. L. Moruzzi, A. R. Williams, Phys. Rev. B 1975, 12, 1257;
    • (1975) Phys. Rev. B , vol.12 , pp. 1257
    • Janak, J.F.1    Moruzzi, V.L.2    Williams, A.R.3
  • 27
    • 33748224817 scopus 로고
    • Angew. Chem. 1992, 31, 187;
    • (1992) Angew. Chem. , vol.31 , pp. 187
  • 31
    • 23244461569 scopus 로고
    • [15c] The tellurium 5s, 5p, 5d, and 5f orbitals were included in the calculations with the 5d and 5f orbitals down-folded, so that they were not included in the basis set. These two orbitals can carry charges without any contribution to the Hamiltonian operators and overlap matrices. To avoid overly large atomic sphere overlap, the interstitial region was filled with empty spheres, for which only the s orbital was included in the basis set. a) O. K. Andersen, Phys. Rev. B 1975, 12, 3060;
    • (1975) Phys. Rev. B , vol.12 , pp. 3060
    • Andersen, O.K.1
  • 34
    • 31044432352 scopus 로고    scopus 로고
    • note
    • 1), where the superscript 0 of U denotes the pure parameter.
  • 35
    • 0000126892 scopus 로고    scopus 로고
    • [17a] with an LDA formula from reference [17b] was used for the calculations. The 5p orbital of the impurity tellurium atom is isolated with respect to the system to avoid double counting and the change of its occupancy. a) S. Y. Savrasov, Phys. Rev. B 1996, 54, 16470;
    • (1996) Phys. Rev. B , vol.54 , pp. 16470
    • Savrasov, S.Y.1
  • 41
    • 31044453966 scopus 로고    scopus 로고
    • note
    • For solid Te-I, the 6s and 5d orbitals are treated as bands. Thus, the change in the number of conduction electrons owing to the variation of the occupancy of the "impurity" Te-5p orbital can be accommodated by the whole crystal. The occupancies of all orbitals in the atom are fixed. Therefore, the dynamic effects of the screening are fully neglected in the calculations.
  • 42
    • 33645898818 scopus 로고
    • [21a] was used to correct the LDA of reference [17b]. a) J. P. Perdew, Y. Wang, Phys. Rev. B 1992, 45, 13244.
    • (1992) Phys. Rev. B , vol.45 , pp. 13244
    • Perdew, J.P.1    Wang, Y.2
  • 43
    • 31044452889 scopus 로고    scopus 로고
    • note
    • The crystallographic data for Te-II were taken from reference [12]. However, since the original unit cell setting was nonstandard, we transformed it into a standard one. The final unit cell parameters are a = 776.07, b = 780.29, c = 735.77 pm, α = 156.66, β = 148.42, γ = 45.75°. The atomic coordinates were also transformed accordingly. In this setting, the helical chain of tellurium atoms runs along the c axis, as it does in Te-I. For the TB-LMTO calculations on Te-II, an 18 x 18 x 18 k mesh was chosen. The other parameters were chosen as for Te-I (see reference [15]). For the FP-LMTO calculations on Te-II, the pseudo-LMTOs were expanded in plane waves up to 8.54, 12.4, and 18.1 Ryd. (240, 412, and 722 plane waves) for the 5s, 5p, and 5d orbitals of Te1, respectively, while for Te2, the pseudo-LMTOs were expanded in plane waves up to 10.0, 14.6, and 21.4 Ryd. (286, 536, and 946 plane waves) for the 5s, 5p, and 5d orbitals, respectively.
  • 44
    • 31044439989 scopus 로고    scopus 로고
    • note
    • The calculated compositions for some band states are ψ(H1) = 95.5 % Te(5s) + 4.14 % Te(5p) + 0.36 % Te(5d); ψ(H5) = 1.12 % Te(5s) + 96.88 % Te(5p) +1.99 % Te(5d); ψ(H9) = 4.31 % Te(5s) + 93.16 % Te(5p) + 2.53 % Te(5d); ψ(H10) = 3.42 % Te(5s) + 88.17 % Te(5p) + 8.41 % Te(5d).
  • 45
    • 31044450086 scopus 로고    scopus 로고
    • note
    • The very good agreement between the TB-LMTO band gap and the experimental value seems accidental, because LDA often underestimates the band gap. Moreover, our FP-LMTO method gives a band gap of only 0.247 eV.
  • 47
    • 31044437278 scopus 로고    scopus 로고
    • note
    • Brillouin zone for Te-I and Te-II:


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.