High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study
Point contact Andreev reflection spectroscopy is employed to extract the effective Fermi-level spin polarization of three distinct compositions from the (Bi[subscript 1−x]Sb[subscript x])[subscript 2] Te[subscript 3] topological insulator family. The end members, Bi[subscript 2] Te[subscript 3] and...
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| Format: | Article |
| Language: | English |
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American Physical Society
2016
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| Online Access: | http://hdl.handle.net/1721.1/104635 https://orcid.org/0000-0002-2480-1211 https://orcid.org/0000-0001-7413-5715 |
| _version_ | 1826205233747853312 |
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| author | Borisov, K. Stamenov, P. Moodera, Jagadeesh Chang, Cui-zu |
| author2 | Massachusetts Institute of Technology. Plasma Science and Fusion Center |
| author_facet | Massachusetts Institute of Technology. Plasma Science and Fusion Center Borisov, K. Stamenov, P. Moodera, Jagadeesh Chang, Cui-zu |
| author_sort | Borisov, K. |
| collection | MIT |
| description | Point contact Andreev reflection spectroscopy is employed to extract the effective Fermi-level spin polarization of three distinct compositions from the (Bi[subscript 1−x]Sb[subscript x])[subscript 2] Te[subscript 3] topological insulator family. The end members, Bi[subscript 2] Te[subscript 3] and Sb[subscript 2] Te[subscript 3], exhibit high polarization of 70(4)% and 57(3)%, respectively. High-field (μ[subscript 0]H=14T) point contact spectroscopy shows carrier depletion close to the Fermi level for these two compositions with small activation gaps of 0.40(4) and 0.28(2) meV, respectively. The almost fully suppressed bulk conductivity in the (Bi[subscript 0.18]Sb[subscript 0.82])[subscript 2] Te[subscript 3] results in an even higher spin polarization of 83(9)%. Further, it is demonstrated that magnetic doping with Cr and V tends to reduce the spin-polarization values with respect to the ones of the pure compositions. Bi[subscript 1.97] Cr[subscript 0.03] Te[subscript 3], Sb[subsript 1.975] Cr[subscript 0.025] Te[subscript 3], Bi[subscript 1.975] V[subscript 0.025] Te[subscript 3], and Sb[subscript 1.97] V [subscipt 0.03] Te[subscript 3] exhibit spin polarization of 52%, 52%, 58%, and 50%, respectively. In view of the rather high effective polarization, nonmagnetic topological insulators close to (Bi[subscript 0.18] Sb[subscript 0.82])[subscript 2] Te[subscript 3] may provide a path towards the characterization of pair-breaking mechanisms in spin-triplet superconductors. |
| first_indexed | 2024-09-23T13:09:28Z |
| format | Article |
| id | mit-1721.1/104635 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T13:09:28Z |
| publishDate | 2016 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1046352022-09-28T12:20:35Z High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study Borisov, K. Stamenov, P. Moodera, Jagadeesh Chang, Cui-zu Massachusetts Institute of Technology. Plasma Science and Fusion Center Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) Moodera, Jagadeesh Chang, Cui-zu Point contact Andreev reflection spectroscopy is employed to extract the effective Fermi-level spin polarization of three distinct compositions from the (Bi[subscript 1−x]Sb[subscript x])[subscript 2] Te[subscript 3] topological insulator family. The end members, Bi[subscript 2] Te[subscript 3] and Sb[subscript 2] Te[subscript 3], exhibit high polarization of 70(4)% and 57(3)%, respectively. High-field (μ[subscript 0]H=14T) point contact spectroscopy shows carrier depletion close to the Fermi level for these two compositions with small activation gaps of 0.40(4) and 0.28(2) meV, respectively. The almost fully suppressed bulk conductivity in the (Bi[subscript 0.18]Sb[subscript 0.82])[subscript 2] Te[subscript 3] results in an even higher spin polarization of 83(9)%. Further, it is demonstrated that magnetic doping with Cr and V tends to reduce the spin-polarization values with respect to the ones of the pure compositions. Bi[subscript 1.97] Cr[subscript 0.03] Te[subscript 3], Sb[subsript 1.975] Cr[subscript 0.025] Te[subscript 3], Bi[subscript 1.975] V[subscript 0.025] Te[subscript 3], and Sb[subscript 1.97] V [subscipt 0.03] Te[subscript 3] exhibit spin polarization of 52%, 52%, 58%, and 50%, respectively. In view of the rather high effective polarization, nonmagnetic topological insulators close to (Bi[subscript 0.18] Sb[subscript 0.82])[subscript 2] Te[subscript 3] may provide a path towards the characterization of pair-breaking mechanisms in spin-triplet superconductors. National Science Foundation (U.S.) (Grants DMR- 1207469 and DMR-0819762 (MIT MRSEC)) United States. Office of Naval Research (Grant N00014-13-1-030) National Science Foundation (U.S.) STC Center for Integrated Quantum Materials (Grant DMR- 1231319) 2016-09-30T22:07:01Z 2016-09-30T22:07:01Z 2016-09 2016-09-13T22:00:10Z Article http://purl.org/eprint/type/JournalArticle 2469-9950 2469-9969 http://hdl.handle.net/1721.1/104635 Borisov, K. et al. “High Fermi-Level Spin Polarization in the ( Bi 1 − X Sb X ) 2 Te 3 Family of Topological Insulators: A Point Contact Andreev Reflection Study.” Physical Review B 94.9 (2016): n. pag. https://orcid.org/0000-0002-2480-1211 https://orcid.org/0000-0001-7413-5715 en http://dx.doi.org/10.1103/PhysRevB.94.094415 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Borisov, K. Stamenov, P. Moodera, Jagadeesh Chang, Cui-zu High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title | High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title_full | High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title_fullStr | High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title_full_unstemmed | High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title_short | High Fermi-level spin polarization in the (Bi[subscript 1−x]Sb[subscript x])2Te[subscript 3] family of topological insulators: A point contact Andreev reflection study |
| title_sort | high fermi level spin polarization in the bi subscript 1 x sb subscript x 2te subscript 3 family of topological insulators a point contact andreev reflection study |
| url | http://hdl.handle.net/1721.1/104635 https://orcid.org/0000-0002-2480-1211 https://orcid.org/0000-0001-7413-5715 |
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