A valley-spin qubit in a carbon nanotube
Although electron spins in III-V semiconductor quantum dots have shown great promise as qubits, hyperfine decoherence remains a major challenge in these materials. Group IV semiconductors possess dominant nuclear species that are spinless, allowing qubit coherence times up to 2 s. In carbon nanotube...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
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2013
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| _version_ | 1826284763037564928 |
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| author | Laird, E Pei, F Kouwenhoven, L |
| author_facet | Laird, E Pei, F Kouwenhoven, L |
| author_sort | Laird, E |
| collection | OXFORD |
| description | Although electron spins in III-V semiconductor quantum dots have shown great promise as qubits, hyperfine decoherence remains a major challenge in these materials. Group IV semiconductors possess dominant nuclear species that are spinless, allowing qubit coherence times up to 2 s. In carbon nanotubes, where the spin-orbit interaction allows for all-electrical qubit manipulation, theoretical predictions of the coherence time vary by at least six orders of magnitude and range up to 10 s or more. Here, we realize a qubit encoded in two nanotube valley-spin states, with coherent manipulation via electrically driven spin resonance mediated by a bend in the nanotube. Readout uses Pauli blockade leakage current through a double quantum dot. Arbitrary qubit rotations are demonstrated and the coherence time is measured for the first time via Hahn echo, allowing comparison with theoretical predictions. The coherence time is found to be ∼65 ns, probably limited by electrical noise. This shows that, even with low nuclear spin abundance, coherence can be strongly degraded if the qubit states are coupled to electric fields. © 2013 Macmillan Publishers Limited. All rights reserved. |
| first_indexed | 2024-03-07T01:18:43Z |
| format | Journal article |
| id | oxford-uuid:8f98ca43-6005-48b1-8596-9c6ac1a48a3d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T01:18:43Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | oxford-uuid:8f98ca43-6005-48b1-8596-9c6ac1a48a3d2022-03-26T23:05:37ZA valley-spin qubit in a carbon nanotubeJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8f98ca43-6005-48b1-8596-9c6ac1a48a3dEnglishSymplectic Elements at Oxford2013Laird, EPei, FKouwenhoven, LAlthough electron spins in III-V semiconductor quantum dots have shown great promise as qubits, hyperfine decoherence remains a major challenge in these materials. Group IV semiconductors possess dominant nuclear species that are spinless, allowing qubit coherence times up to 2 s. In carbon nanotubes, where the spin-orbit interaction allows for all-electrical qubit manipulation, theoretical predictions of the coherence time vary by at least six orders of magnitude and range up to 10 s or more. Here, we realize a qubit encoded in two nanotube valley-spin states, with coherent manipulation via electrically driven spin resonance mediated by a bend in the nanotube. Readout uses Pauli blockade leakage current through a double quantum dot. Arbitrary qubit rotations are demonstrated and the coherence time is measured for the first time via Hahn echo, allowing comparison with theoretical predictions. The coherence time is found to be ∼65 ns, probably limited by electrical noise. This shows that, even with low nuclear spin abundance, coherence can be strongly degraded if the qubit states are coupled to electric fields. © 2013 Macmillan Publishers Limited. All rights reserved. |
| spellingShingle | Laird, E Pei, F Kouwenhoven, L A valley-spin qubit in a carbon nanotube |
| title | A valley-spin qubit in a carbon nanotube |
| title_full | A valley-spin qubit in a carbon nanotube |
| title_fullStr | A valley-spin qubit in a carbon nanotube |
| title_full_unstemmed | A valley-spin qubit in a carbon nanotube |
| title_short | A valley-spin qubit in a carbon nanotube |
| title_sort | valley spin qubit in a carbon nanotube |
| work_keys_str_mv | AT lairde avalleyspinqubitinacarbonnanotube AT peif avalleyspinqubitinacarbonnanotube AT kouwenhovenl avalleyspinqubitinacarbonnanotube AT lairde valleyspinqubitinacarbonnanotube AT peif valleyspinqubitinacarbonnanotube AT kouwenhovenl valleyspinqubitinacarbonnanotube |