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セガワ コウジ
SEGAWA KOJI
瀬川 耕司 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2015/04 |
| 形態種別 | 研究論文 |
| 標題 | Infrared probe of the bulk insulating response in Bi2-xSbxTe3-ySey topological insulator alloys |
| 執筆形態 | その他 |
| 掲載誌名 | PHYSICAL REVIEW B |
| 出版社・発行元 | AMER PHYSICAL SOC |
| 巻・号・頁 | 91(16) |
| 著者・共著者 | K. W. Post,Y. S. Lee,B. C. Chapler,A. A. Schafgans,Mario Novak,A. A. Taskin,Kouji Segawa,M. D. Goldflam,H. T. Stinson,Yoichi Ando,D. N. Basov |
| 概要 | We have investigated the electronic structure and carrier dynamics of the topological insulator Bi2-xSbxTe3-ySey, for x = 0.5, y = 1.3 and x = 1, y = 2, using infrared spectroscopy. Our results show that both of these BSTS alloys are highly insulating in the bulk, with analysis of the infrared data indicating an upper limit to the carrier density of 4.4 x 10(17) cm(-3). Furthermore, analysis of the interband transitions of Bi1.5Sb0.5Te1.7Se1.3 revealed distinct band-structure critical points, which suggest high crystallographic order of our crystals. Motivated by the low carrier density and crystallographic order identified in these compounds, we searched for the Landau level transitions associated with the surface states through magneto-optical measurements in the far infrared range. We failed to observe any indications of the Landau level resonances at fields up to 8 T in sharp contrast with our earlier finding for a related Bi1-xSbx alloy. We discuss factors that may be responsible for suppressed magneto-optics response of these single crystals. |
| DOI | 10.1103/PhysRevB.91.165202 |
| ISSN | 1098-0121/1550-235X |
| PermalinkURL | https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84929206895&origin=inward |