Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases
We present thermopower S and resistance R measurements on GaAs-based mesoscopic two-dimensional electron gases as functions of the electron density n _s . At high n _s we observe good agreement between the measured S and S _MOTT , the Mott prediction for a non-interacting metal. As n _s is lowered,...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2014-01-01
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| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/16/8/085009 |
| _version_ | 1797751333922537472 |
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| author | Vijay Narayan Eugene Kogan Chris Ford Michael Pepper Moshe Kaveh Jonathan Griffiths Geb Jones Harvey Beere Dave Ritchie |
| author_facet | Vijay Narayan Eugene Kogan Chris Ford Michael Pepper Moshe Kaveh Jonathan Griffiths Geb Jones Harvey Beere Dave Ritchie |
| author_sort | Vijay Narayan |
| collection | DOAJ |
| description | We present thermopower S and resistance R measurements on GaAs-based mesoscopic two-dimensional electron gases as functions of the electron density n _s . At high n _s we observe good agreement between the measured S and S _MOTT , the Mott prediction for a non-interacting metal. As n _s is lowered, we observe a crossover from Mott-like behaviour to that where S shows strong oscillations and even sign changes. Remarkably, there are absolutely no features in R corresponding to those in S . In fact, R is devoid of even any universal conductance fluctuations. A statistical analysis of the thermopower oscillations from two devices of dissimilar dimensions suggest a universal nature of the oscillations. We critically examine whether they can be mesoscopic fluctuations of the kind described by Lesovik and Khmelnitskii (1988 Sov. Phys. JETP http://dx.doi.org/10.1134/s0021364007150131 67 http://dx.doi.org/10.1134/s0021364007150131 ). |
| first_indexed | 2024-03-12T16:47:58Z |
| format | Article |
| id | doaj.art-c9dde1d7ead04b6c94c287ba17de1f2c |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:47:58Z |
| publishDate | 2014-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-c9dde1d7ead04b6c94c287ba17de1f2c2023-08-08T11:30:56ZengIOP PublishingNew Journal of Physics1367-26302014-01-0116808500910.1088/1367-2630/16/8/085009Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gasesVijay Narayan0Eugene Kogan1Chris Ford2Michael Pepper3Moshe Kaveh4Jonathan Griffiths5Geb Jones6Harvey Beere7Dave Ritchie8Cavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKDepartment of Physics, Bar-Ilan University , Ramat-Gan 52900, IsraelCavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKDepartment of Electronic and Electrical Engineering, University College London , Torrington Place, London WC1E 7JE, UKDepartment of Physics, Bar-Ilan University , Ramat-Gan 52900, IsraelCavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKCavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKCavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKCavendish Laboratory, University of Cambridge , J J Thomson Avenue, Cambridge CB3 0HE, UKWe present thermopower S and resistance R measurements on GaAs-based mesoscopic two-dimensional electron gases as functions of the electron density n _s . At high n _s we observe good agreement between the measured S and S _MOTT , the Mott prediction for a non-interacting metal. As n _s is lowered, we observe a crossover from Mott-like behaviour to that where S shows strong oscillations and even sign changes. Remarkably, there are absolutely no features in R corresponding to those in S . In fact, R is devoid of even any universal conductance fluctuations. A statistical analysis of the thermopower oscillations from two devices of dissimilar dimensions suggest a universal nature of the oscillations. We critically examine whether they can be mesoscopic fluctuations of the kind described by Lesovik and Khmelnitskii (1988 Sov. Phys. JETP http://dx.doi.org/10.1134/s0021364007150131 67 http://dx.doi.org/10.1134/s0021364007150131 ).https://doi.org/10.1088/1367-2630/16/8/085009thermopowermesoscopic2DEG |
| spellingShingle | Vijay Narayan Eugene Kogan Chris Ford Michael Pepper Moshe Kaveh Jonathan Griffiths Geb Jones Harvey Beere Dave Ritchie Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases New Journal of Physics thermopower mesoscopic 2DEG |
| title | Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases |
| title_full | Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases |
| title_fullStr | Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases |
| title_full_unstemmed | Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases |
| title_short | Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases |
| title_sort | density dependent thermopower oscillations in mesoscopic two dimensional electron gases |
| topic | thermopower mesoscopic 2DEG |
| url | https://doi.org/10.1088/1367-2630/16/8/085009 |
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