Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13

Daniel I. Bilc, Paul Larson, S. D. Mahanti, Mercouri G Kanatzidis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

K2Bi8Se13 belongs to a class of complex chalcogenides which show potential for superior thermoelectric performance. This compound forms in two distinct phases, α and β. The β-phase, which has several sites with mixed K/Bi occupancy is a better thermoelectric. To understand the origin of this difference we have carried out electronic structure calculations within ab initio density functional theory using full potential linearized augmented plane wave (FLAPW) method. The generalized gradient approximation was used to treat the exchange and correlation potential. Spin-orbit interaction (SOI) was incorporated using a second variational procedure. The α-phase is found to be a semiconductor with an indirect band gap of 0.47eV compared to 0.76eV for the observed direct optical gap. For the β-phase we have chosen two different ordered structures with full occupancies of K and Bi atoms at the "mixed sites". The system is a semi-metal for both the ordered structures. To incorporate the effect of mixed occupancy we have chosen a 1×1×2 supercell with an alternative K/Bi occupancy at the "mixed sites". The superlattice ordering gives a semiconductor with an indirect gap of 0.38eV. Mixed occupancy is crucial for the system to be a semiconductor because the Bi atoms at the "mixed sites" stabilize the p orbitals of the neighboring Se atoms by lowering their energy, and opening up a gap at the chemical potential.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsG.S. Nolas, J. Yang, T.P. Hogan, D.C. Johnson
Pages161-166
Number of pages6
Volume793
Publication statusPublished - 2003
EventThermoelectric Materials 2003 - Research and Applications - Boston, MA., United States
Duration: Dec 1 2003Dec 3 2003

Other

OtherThermoelectric Materials 2003 - Research and Applications
CountryUnited States
CityBoston, MA.
Period12/1/0312/3/03

Fingerprint

Electronic structure
Semiconductor materials
Atoms
Metalloids
Chalcogenides
Chemical potential
Density functional theory
Orbits
Energy gap
Metals

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Bilc, D. I., Larson, P., Mahanti, S. D., & Kanatzidis, M. G. (2003). Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13. In G. S. Nolas, J. Yang, T. P. Hogan, & D. C. Johnson (Eds.), Materials Research Society Symposium - Proceedings (Vol. 793, pp. 161-166)

Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13. / Bilc, Daniel I.; Larson, Paul; Mahanti, S. D.; Kanatzidis, Mercouri G.

Materials Research Society Symposium - Proceedings. ed. / G.S. Nolas; J. Yang; T.P. Hogan; D.C. Johnson. Vol. 793 2003. p. 161-166.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Bilc, DI, Larson, P, Mahanti, SD & Kanatzidis, MG 2003, Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13. in GS Nolas, J Yang, TP Hogan & DC Johnson (eds), Materials Research Society Symposium - Proceedings. vol. 793, pp. 161-166, Thermoelectric Materials 2003 - Research and Applications, Boston, MA., United States, 12/1/03.
Bilc DI, Larson P, Mahanti SD, Kanatzidis MG. Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13. In Nolas GS, Yang J, Hogan TP, Johnson DC, editors, Materials Research Society Symposium - Proceedings. Vol. 793. 2003. p. 161-166
Bilc, Daniel I. ; Larson, Paul ; Mahanti, S. D. ; Kanatzidis, Mercouri G. / Effect of K/Bi ordering on the electronic structure of K2Bi 8Se13. Materials Research Society Symposium - Proceedings. editor / G.S. Nolas ; J. Yang ; T.P. Hogan ; D.C. Johnson. Vol. 793 2003. pp. 161-166
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