Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators
In an ultrathin topological insulator (TI) film, a hybridization gap opens in the TI surface states, and the system is expected to become either a trivial insulator or a quantum spin Hall insulator when the chemical potential is within the hybridization gap. Here we show, however, that these insulat...
| Main Authors: | , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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American Physical Society
2019
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| Online Access: | http://hdl.handle.net/1721.1/119872 https://orcid.org/0000-0001-7413-5715 https://orcid.org/0000-0002-9350-8756 https://orcid.org/0000-0002-2480-1211 |
| _version_ | 1826188535859773440 |
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| author | Lee, G. H. Huang, K.-F. Shain, K. Lee, S.-P. Ward, J. Kim, P. Halperin, B. I. Yacoby, A. Nandi, Debaleena Skinner, Barbara Chang, Cui-zu Ou, Yunbo Moodera, Jagadeesh |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Lee, G. H. Huang, K.-F. Shain, K. Lee, S.-P. Ward, J. Kim, P. Halperin, B. I. Yacoby, A. Nandi, Debaleena Skinner, Barbara Chang, Cui-zu Ou, Yunbo Moodera, Jagadeesh |
| author_sort | Lee, G. H. |
| collection | MIT |
| description | In an ultrathin topological insulator (TI) film, a hybridization gap opens in the TI surface states, and the system is expected to become either a trivial insulator or a quantum spin Hall insulator when the chemical potential is within the hybridization gap. Here we show, however, that these insulating states are destroyed by the presence of a large and long-range-correlated disorder potential, which converts the expected insulator into a metal. We perform transport measurements in ultrathin dual-gated topological insulator films as a function of temperature, gate voltage, and magnetic field, and we observe a metalliclike nonquantized conductivity, which exhibits a weak antilocalizationlike cusp at low magnetic fields and gives way to a nonsaturating linear magnetoresistance at large fields. We explain these results by considering the disordered network of electron- and hole-type puddles induced by charged impurities. We argue theoretically that such disorder can produce an insulator-to-metal transition as a function of increasing disorder strength, and we derive a condition on the band gap and the impurity concentration necessary to observe the insulating state. We also explain the linear magnetoresistance in terms of strong spatial fluctuations of the local conductivity using both numerical simulations and a theoretical scaling argument. |
| first_indexed | 2024-09-23T08:01:12Z |
| format | Article |
| id | mit-1721.1/119872 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:01:12Z |
| publishDate | 2019 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1198722022-09-23T10:19:40Z Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators Lee, G. H. Huang, K.-F. Shain, K. Lee, S.-P. Ward, J. Kim, P. Halperin, B. I. Yacoby, A. Nandi, Debaleena Skinner, Barbara Chang, Cui-zu Ou, Yunbo Moodera, Jagadeesh Massachusetts Institute of Technology. Department of Physics Massachusetts Institute of Technology. Plasma Science and Fusion Center Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) Nandi, Debaleena Skinner, Barbara Chang, Cui-zu Ou, Yunbo Moodera, Jagadeesh In an ultrathin topological insulator (TI) film, a hybridization gap opens in the TI surface states, and the system is expected to become either a trivial insulator or a quantum spin Hall insulator when the chemical potential is within the hybridization gap. Here we show, however, that these insulating states are destroyed by the presence of a large and long-range-correlated disorder potential, which converts the expected insulator into a metal. We perform transport measurements in ultrathin dual-gated topological insulator films as a function of temperature, gate voltage, and magnetic field, and we observe a metalliclike nonquantized conductivity, which exhibits a weak antilocalizationlike cusp at low magnetic fields and gives way to a nonsaturating linear magnetoresistance at large fields. We explain these results by considering the disordered network of electron- and hole-type puddles induced by charged impurities. We argue theoretically that such disorder can produce an insulator-to-metal transition as a function of increasing disorder strength, and we derive a condition on the band gap and the impurity concentration necessary to observe the insulating state. We also explain the linear magnetoresistance in terms of strong spatial fluctuations of the local conductivity using both numerical simulations and a theoretical scaling argument. Gordon and Betty Moore Foundation (Grant GBMF4531) National Science Foundation (U.S.) (Grant DMR-1708688) United States. Army Research Office (Grant W911NF16-1-0491) United States. Army Research Office (Grant W911NF-17-1-0023) United States. Army Research Office (Grant W911NF-18-1-0316) 2019-01-08T16:31:25Z 2019-01-08T16:31:25Z 2018-12 2018-08 2018-12-19T18:00:17Z Article http://purl.org/eprint/type/JournalArticle 2469-9950 2469-9969 http://hdl.handle.net/1721.1/119872 Nandi, D. et al. "Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators." Physical Review B 98, 21 (December 2018): 214203 © 2018 American Physical Society https://orcid.org/0000-0001-7413-5715 https://orcid.org/0000-0002-9350-8756 https://orcid.org/0000-0002-2480-1211 en http://dx.doi.org/10.1103/PhysRevB.98.214203 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 | Lee, G. H. Huang, K.-F. Shain, K. Lee, S.-P. Ward, J. Kim, P. Halperin, B. I. Yacoby, A. Nandi, Debaleena Skinner, Barbara Chang, Cui-zu Ou, Yunbo Moodera, Jagadeesh Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title | Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title_full | Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title_fullStr | Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title_full_unstemmed | Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title_short | Signatures of long-range-correlated disorder in the magnetotransport of ultrathin topological insulators |
| title_sort | signatures of long range correlated disorder in the magnetotransport of ultrathin topological insulators |
| url | http://hdl.handle.net/1721.1/119872 https://orcid.org/0000-0001-7413-5715 https://orcid.org/0000-0002-9350-8756 https://orcid.org/0000-0002-2480-1211 |
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