Role of K/Bi disorder in the electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}.
Abstract
We have carried out tunneling spectroscopy and first-principles studies for {beta}-K{sub 2}Bi{sub 8}Se{sub 13}, a promising thermoelectric material with partially disordered mixed K/Bi sites. The tunneling data, obtained with a scanning tunneling microscope (STM), show that the system is a semiconductor with a band gap of {approx}0.4 eV and band-tail states near the valence-band top and the conduction-band bottom. First-principles calculations, on the other hand, show that {beta}-K{sub 2}Bi{sub 8}Se{sub 13} can be semimetallic or semiconducting depending on the arrangements of the K and Bi atoms in the mixed sites. The electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13} near the band-gap region is largely determined by unbonded Se p states and states associated with strained bonds which are present due to K/Bi disorder and by the Bi p-Se p hybridization which tends to drive the system toward metallicity. Among the different K/Bi arrangements investigated, we have identified a structural model (quasidisordered structure) that is able to satisfactorily reproduce the atomic and electronic structures of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}; i.e., the local composition in the mixed channels as observed experimentally and the band gap and tails as seen in the STM measurements. We argue that transport properties of {beta}-K{sub 2}Bi{sub 8}Se{submore »
- Authors:
- Publication Date:
- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC); USDOD; National Science Foundation (NSF)
- OSTI Identifier:
- 966349
- Report Number(s):
- ANL/MSD/JA-65425
Journal ID: ISSN 1098-0121; TRN: US200921%%373
- DOE Contract Number:
- DE-AC02-06CH11357
- Resource Type:
- Journal Article
- Journal Name:
- Phys. Rev. B
- Additional Journal Information:
- Journal Volume: 80; Journal Issue: 2009; Journal ID: ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
- Subject:
- 36 MATERIALS SCIENCE; ATOMS; ELECTRONIC STRUCTURE; HYBRIDIZATION; MICROSCOPES; P STATES; SPECTROSCOPY; STRUCTURAL MODELS; THERMOELECTRIC MATERIALS; TRANSPORT; TUNNELING
Citation Formats
Hoang, K, Tomic, A, Mahanti, S D, Kyratsi, T, Chung, D -Y, Tessmer, S H, Kanatzidis, M G, Materials Science Division, at Santa Barbara, Uiv California, Michigan State Univ., Univ. Cyprus, and Northwestern Univ. Role of K/Bi disorder in the electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}.. United States: N. p., 2009.
Web. doi:10.1103/PhysRevB.80.125112.
Hoang, K, Tomic, A, Mahanti, S D, Kyratsi, T, Chung, D -Y, Tessmer, S H, Kanatzidis, M G, Materials Science Division, at Santa Barbara, Uiv California, Michigan State Univ., Univ. Cyprus, & Northwestern Univ. Role of K/Bi disorder in the electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}.. United States. https://doi.org/10.1103/PhysRevB.80.125112
Hoang, K, Tomic, A, Mahanti, S D, Kyratsi, T, Chung, D -Y, Tessmer, S H, Kanatzidis, M G, Materials Science Division, at Santa Barbara, Uiv California, Michigan State Univ., Univ. Cyprus, and Northwestern Univ. 2009.
"Role of K/Bi disorder in the electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}.". United States. https://doi.org/10.1103/PhysRevB.80.125112.
@article{osti_966349,
title = {Role of K/Bi disorder in the electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}.},
author = {Hoang, K and Tomic, A and Mahanti, S D and Kyratsi, T and Chung, D -Y and Tessmer, S H and Kanatzidis, M G and Materials Science Division and at Santa Barbara, Uiv California and Michigan State Univ. and Univ. Cyprus and Northwestern Univ.},
abstractNote = {We have carried out tunneling spectroscopy and first-principles studies for {beta}-K{sub 2}Bi{sub 8}Se{sub 13}, a promising thermoelectric material with partially disordered mixed K/Bi sites. The tunneling data, obtained with a scanning tunneling microscope (STM), show that the system is a semiconductor with a band gap of {approx}0.4 eV and band-tail states near the valence-band top and the conduction-band bottom. First-principles calculations, on the other hand, show that {beta}-K{sub 2}Bi{sub 8}Se{sub 13} can be semimetallic or semiconducting depending on the arrangements of the K and Bi atoms in the mixed sites. The electronic structure of {beta}-K{sub 2}Bi{sub 8}Se{sub 13} near the band-gap region is largely determined by unbonded Se p states and states associated with strained bonds which are present due to K/Bi disorder and by the Bi p-Se p hybridization which tends to drive the system toward metallicity. Among the different K/Bi arrangements investigated, we have identified a structural model (quasidisordered structure) that is able to satisfactorily reproduce the atomic and electronic structures of {beta}-K{sub 2}Bi{sub 8}Se{sub 13}; i.e., the local composition in the mixed channels as observed experimentally and the band gap and tails as seen in the STM measurements. We argue that transport properties of {beta}-K{sub 2}Bi{sub 8}Se{sub 13} can be qualitatively understood in terms of the electronic structure obtained in calculations using the above structural model.},
doi = {10.1103/PhysRevB.80.125112},
url = {https://www.osti.gov/biblio/966349},
journal = {Phys. Rev. B},
issn = {1098-0121},
number = 2009,
volume = 80,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2009},
month = {Thu Jan 01 00:00:00 EST 2009}
}