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Breslavetz I, Delhomme A, Pelini T, Pawbake A, Vaclavkova D, Orlita M, Potemski M, Measson MA, Faugeras C. Spatially resolved optical spectroscopy in extreme environment of low temperature, high magnetic fields and high pressure. Rev Sci Instrum 2021; 92:123909. [PMID: 34972398 DOI: 10.1063/5.0070934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/01/2021] [Indexed: 06/14/2023]
Abstract
We present an experimental setup developed to perform optical spectroscopy experiments (Raman scattering and photoluminescence measurements) with a micrometer spatial resolution in an extreme environment of low temperature, high magnetic field, and high pressure. This unique experimental setup, to the best of our knowledge, allows us to deeply explore the phase diagram of condensed matter systems by independently tuning these three thermodynamic parameters while monitoring the low-energy excitations (electronic, phononic, or magnetic excitations) to spatially map the Raman scattering response or to investigate objects with low dimensions. We apply this technique to bulk FePS3, a layered antiferromagnet with a Néel temperature of T ≈ 120 K.
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Affiliation(s)
- I Breslavetz
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - A Delhomme
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - T Pelini
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - A Pawbake
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - D Vaclavkova
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - M Orlita
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - M Potemski
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - M-A Measson
- Institut Neel, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | - C Faugeras
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
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2
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Grzeszczyk M, Szpakowski J, Slobodeniuk AO, Kazimierczuk T, Bhatnagar M, Taniguchi T, Watanabe K, Kossacki P, Potemski M, Babiński A, Molas MR. The optical response of artificially twisted MoS[Formula: see text] bilayers. Sci Rep 2021; 11:17037. [PMID: 34426607 PMCID: PMC8382769 DOI: 10.1038/s41598-021-95700-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom-the interlayer twist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS[Formula: see text] encapsulated in hexagonal BN with interlayer twist angle ranging from 0[Formula: see text] to 60[Formula: see text] using Raman scattering and photoluminescence spectroscopies. It is found that the strength of the interlayer coupling in the studied BLs can be estimated using the energy dependence of indirect emission versus the A[Formula: see text]-E[Formula: see text] energy separation. Due to the hybridization of electronic states in the valence band, the emission line related to the interlayer exciton is apparent in both the natural (2H) and artificial (62[Formula: see text]) MoS[Formula: see text] BLs, while it is absent in the structures with other twist angles. The interlayer coupling energy is estimated to be of about 50 meV. The effect of temperature on energies and intensities of the direct and indirect emission lines in MoS[Formula: see text] BLs is also quantified.
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Affiliation(s)
- M. Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - J. Szpakowski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - A. O. Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - T. Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Bhatnagar
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - T. Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - K. Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - P. Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - A. Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. R. Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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Smoleński T, Kazimierczuk T, Goryca M, Nogajewski K, Potemski M, Kossacki P. Valley pseudospin relaxation of charged excitons in monolayer MoTe 2. J Phys Condens Matter 2021; 33:025701. [PMID: 33055370 DOI: 10.1088/1361-648x/abb1cb] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Zeeman effect induced by the magnetic field introduces a splitting between the two valleys at K + and K - points of the Brillouin zone in monolayer semiconducting transition metal dichalcogenides. In consequence, the photoluminescence signal exhibits a field dependent degree of circular polarization. We present a comprehensive study of this effect in the case of a trion in monolayer MoTe2, showing that although time integrated data allows us to deduce a g-factor of the trion state, such an analysis cannot be substantiated by the timescales revealed in the time-resolved experiments.
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Affiliation(s)
- T Smoleński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
- Institute for Quantum Electronics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - M Goryca
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - K Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - M Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnetiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 rue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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4
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Zinkiewicz M, Slobodeniuk AO, Kazimierczuk T, Kapuściński P, Oreszczuk K, Grzeszczyk M, Bartos M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Neutral and charged dark excitons in monolayer WS 2. Nanoscale 2020; 12:18153-18159. [PMID: 32853305 DOI: 10.1039/d0nr04243a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.
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Affiliation(s)
- M Zinkiewicz
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - A O Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Praha 2 CZ-121 16, Czech Republic
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - K Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland. and Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
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5
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Robert C, Han B, Kapuscinski P, Delhomme A, Faugeras C, Amand T, Molas MR, Bartos M, Watanabe K, Taniguchi T, Urbaszek B, Potemski M, Marie X. Measurement of the spin-forbidden dark excitons in MoS 2 and MoSe 2 monolayers. Nat Commun 2020; 11:4037. [PMID: 32788704 PMCID: PMC7423942 DOI: 10.1038/s41467-020-17608-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/08/2020] [Indexed: 11/13/2022] Open
Abstract
Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30 T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14 meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field.
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Affiliation(s)
- C Robert
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
| | - B Han
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
| | - P Kapuscinski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - A Delhomme
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France.
| | - T Amand
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - B Urbaszek
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 38042, Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
| | - X Marie
- University of Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
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6
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Łopion A, Goryca M, Smoleński T, Oreszczuk K, Nogajewski K, Molas MR, Potemski M, Kossacki P. Temperature dependence of photoluminescence lifetime of atomically-thin WSe 2 layer. Nanotechnology 2020; 31:135002. [PMID: 31825902 DOI: 10.1088/1361-6528/ab60ca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
At cryogenic temperatures, the photoluminescence (PL) spectrum of monolayer WSe2 features a number of lines related to the recombination of so-called localized excitons (LEs). The intensity of these lines strongly decreases with increasing temperature. In order to understand the mechanism behind this phenomenon we carried out a time-resolved experiment, which revealed a similar trend in the PL decay time. Our results identify the opening of additional non-radiative relaxation channels as a primary cause of the observed temperature quenching of the LEs' PL.
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Affiliation(s)
- A Łopion
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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7
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Molas MR, Slobodeniuk AO, Nogajewski K, Bartos M, Bala Ł, Babiński A, Watanabe K, Taniguchi T, Faugeras C, Potemski M. Energy Spectrum of Two-Dimensional Excitons in a Nonuniform Dielectric Medium. Phys Rev Lett 2019; 123:136801. [PMID: 31697524 DOI: 10.1103/physrevlett.123.136801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate that, in monolayers (MLs) of semiconducting transition metal dichalcogenides, the s-type Rydberg series of excitonic states follows a simple energy ladder: ε_{n}=-Ry^{*}/(n+δ)^{2}, n=1,2,…, in which Ry^{*} is very close to the Rydberg energy scaled by the dielectric constant of the medium surrounding the ML and by the reduced effective electron-hole mass, whereas the ML polarizability is accounted for only by δ. This is justified by the analysis of experimental data on excitonic resonances, as extracted from magneto-optical measurements of a high-quality WSe_{2} ML encapsulated in hexagonal boron nitride (hBN), and well reproduced with an analytically solvable Schrödinger equation when approximating the electron-hole potential in the form of a modified Kratzer potential. Applying our convention to other MoSe_{2}, WS_{2}, MoS_{2} MLs encapsulated in hBN, we estimate an apparent magnitude of δ for each of the studied structures. Intriguingly, δ is found to be close to zero for WSe_{2} as well as for MoS_{2} monolayers, what implies that the energy ladder of excitonic states in these two-dimensional structures resembles that of Rydberg states of a three-dimensional hydrogen atom.
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Affiliation(s)
- M R Molas
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A O Slobodeniuk
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 61200 Brno, Czech Republic
| | - Ł Bala
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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8
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Molas MR, Slobodeniuk AO, Kazimierczuk T, Nogajewski K, Bartos M, Kapuściński P, Oreszczuk K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Basko DM, Potemski M. Probing and Manipulating Valley Coherence of Dark Excitons in Monolayer WSe_{2}. Phys Rev Lett 2019; 123:096803. [PMID: 31524465 DOI: 10.1103/physrevlett.123.096803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 06/10/2023]
Abstract
Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong spin-orbit interaction and the resulting ordering of the spin-split subbands in the valence and conduction bands makes the lowest-lying excitons in WX_{2} (X being S or Se) spin forbidden and optically dark. With polarization-resolved photoluminescence experiments performed on a WSe_{2} monolayer encapsulated in a hexagonal boron nitride, we show how the intrinsic exchange interaction in combination with the applied in-plane and/or out-of-plane magnetic fields enables one to probe and manipulate the valley degree of freedom of the dark excitons.
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Affiliation(s)
- M R Molas
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - A O Slobodeniuk
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, 27 Wybrzeże Wyspiańskiego, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - D M Basko
- Laboratoire de Physique et Modélisation des Milieux Condensés, Université Grenoble Alpes and CNRS, 25 avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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9
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Bovkun LS, Ikonnikov AV, Aleshkin VY, Spirin KE, Gavrilenko VI, Mikhailov NN, Dvoretskii SA, Teppe F, Piot BA, Potemski M, Orlita M. Landau level spectroscopy of valence bands in HgTe quantum wells: effects of symmetry lowering. J Phys Condens Matter 2019; 31:145501. [PMID: 30634183 DOI: 10.1088/1361-648x/aafdf0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Landau level spectroscopy technique has been used to explore the electronic structure of the valence band in a series of p-type HgTe/HgCdTe quantum wells with both normal and inverted ordering of bands. We find that the standard axial-symmetric 4-band Kane model, which is nowadays widely applied in physics of HgTe-based topological materials, does not fully account for the complex magneto-optical response observed in our experiments-notably, for the unexpected avoided crossings of excitations and for the appearance of transitions that are electric-dipole forbidden within this model. Nevertheless, reasonable agreement with experiments is achieved when the standard model is expanded to include effects of bulk and interface inversion asymmetries. These remove the axial symmetry, and among other, profoundly modify the shape of valence bands.
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Affiliation(s)
- L S Bovkun
- Institute for Physics of Microstructures RAS, 603950 Nizhny Novgorod, Russia. Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS-UGA-UPS-INSA-EMFL, 38042 Grenoble, France
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10
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Grzeszczyk M, Gołasa K, Molas MR, Nogajewski K, Zinkiewicz M, Potemski M, Wysmołek A, Babiński A. Raman scattering from the bulk inactive out-of-plane [Formula: see text] mode in few-layer MoTe 2. Sci Rep 2018; 8:17745. [PMID: 30531971 PMCID: PMC6288152 DOI: 10.1038/s41598-018-35510-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/05/2018] [Indexed: 11/17/2022] Open
Abstract
We report a study of Raman scattering in few-layer MoTe2 focused on high-frequency out-of-plane vibrational modes near 291 cm-1 which are associated with the bulk-inactive [Formula: see text] mode. Our temperature-dependent measurements reveal a double peak structure of the feature related to these modes in the Raman scattering spectra of 4- and 5-layer MoTe2. In accordance with literature data, the doublet's lower- and higher-energy components are ascribed to the Raman-active A1g/[Formula: see text] vibrations involving, respectively, only the inner and surface layers. We demonstrate a strong enhancement of the inner mode's intensity at low temperature for 1.91 eV and 1.96 eV laser light excitation which suggests a resonant character of the Raman scattering processes probed under such conditions. A resonance of the laser light with a singularity of the electronic density of states at the M point of the MoTe2 Brillouin zone is proposed to be responsible for the observed effects.
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Affiliation(s)
- M. Grzeszczyk
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - K. Gołasa
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. R. Molas
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - K. Nogajewski
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - M. Zinkiewicz
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Potemski
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - A. Wysmołek
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - A. Babiński
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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11
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Vaclavkova D, Wyzula J, Nogajewski K, Bartos M, Slobodeniuk AO, Faugeras C, Potemski M, Molas MR. Singlet and triplet trions in WS 2 monolayer encapsulated in hexagonal boron nitride. Nanotechnology 2018; 29:325705. [PMID: 29781447 DOI: 10.1088/1361-6528/aac65c] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Embedding a WS2 monolayer in flakes of hexagonal boron nitride allowed us to resolve and study the photoluminescence response due to both singlet and triplet states of negatively charged excitons (trions) in this atomically thin semiconductor. The energy separation between the singlet and triplet states has been found to be relatively small reflecting rather weak effects of the electron-electron exchange interaction for the trion triplet in a WS2 monolayer, which involves two electrons with the same spin but from different valleys. Polarization-resolved experiments demonstrate that the helicity of the excitation light is better preserved in the emission spectrum of the triplet trion than in that of the singlet trion. Finally, the singlet (intravalley) trions are found to be observable even at ambient conditions whereas the emission due to the triplet (intervalley) trions is only efficient at low temperatures.
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Affiliation(s)
- D Vaclavkova
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, F-38042 Grenoble, France. Department of Experimental Physics, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czechia
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12
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Akrap A, Hakl M, Tchoumakov S, Crassee I, Kuba J, Goerbig MO, Homes CC, Caha O, Novák J, Teppe F, Desrat W, Koohpayeh S, Wu L, Armitage NP, Nateprov A, Arushanov E, Gibson QD, Cava RJ, van der Marel D, Piot BA, Faugeras C, Martinez G, Potemski M, Orlita M. Magneto-Optical Signature of Massless Kane Electrons in Cd_{3}As_{2}. Phys Rev Lett 2016; 117:136401. [PMID: 27715109 DOI: 10.1103/physrevlett.117.136401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 06/06/2023]
Abstract
We report on optical reflectivity experiments performed on Cd_{3}As_{2} over a broad range of photon energies and magnetic fields. The observed response clearly indicates the presence of 3D massless charge carriers. The specific cyclotron resonance absorption in the quantum limit implies that we are probing massless Kane electrons rather than symmetry-protected 3D Dirac particles. The latter may appear at a smaller energy scale and are not directly observed in our infrared experiments.
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Affiliation(s)
- A Akrap
- DQMP, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - M Hakl
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - S Tchoumakov
- LPS, Université Paris-Sud, Université Paris-Saclay, CNRS UMR 8502, 91405 Orsay, France
| | - I Crassee
- GAP-Biophotonics, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - J Kuba
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
- CEITEC BUT, Brno University of Technology, 616 00 Brno, Czech Republic
| | - M O Goerbig
- LPS, Université Paris-Sud, Université Paris-Saclay, CNRS UMR 8502, 91405 Orsay, France
| | - C C Homes
- CMPMS, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - O Caha
- CEITEC MU, Masaryk University, Faculty of Science, 61137 Brno, Czech Republic
| | - J Novák
- CEITEC MU, Masaryk University, Faculty of Science, 61137 Brno, Czech Republic
| | - F Teppe
- Laboratoire Charles Coulomb, CNRS, Université Montpellier, 34095 Montpellier, France
| | - W Desrat
- Laboratoire Charles Coulomb, CNRS, Université Montpellier, 34095 Montpellier, France
| | - S Koohpayeh
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - L Wu
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - N P Armitage
- The Institute for Quantum Matter, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - A Nateprov
- Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Chisinau, Moldova
| | - E Arushanov
- Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Chisinau, Moldova
| | - Q D Gibson
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | | | - B A Piot
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - C Faugeras
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - G Martinez
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Orlita
- LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
- Institute of Physics, Charles University in Prague, 12116 Prague, Czech Republic
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13
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Molas MR, Nicolet AAL, Piętka B, Babiński A, Potemski M. The excited spin-triplet state of a charged exciton in quantum dots. J Phys Condens Matter 2016; 28:365301. [PMID: 27391126 DOI: 10.1088/0953-8984/28/36/365301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on spectroscopic studies of resonances related to ladder of states of a charged exciton in single GaAlAs/AlAs quantum dot structures. Polarization-resolved photoluminescence, photoluminescence excitation and photon-correlation measurements were performed at low (T = 4.2 K) temperature also in magnetic field applied in Faraday configuration. The investigated resonances are assigned to three different configurations of a positively charged exciton. Together with a singlet ground state and a conventional triplet state (involving an electron from the ground state electronic s-shell), an excited triplet state, which involved an electron from the excited electronic p-shell was identified in single dots. The appearance of an emission line related to the latter complex is due to a partially suppressed electron relaxation in the investigated dots. An analysis of this emission line allows us to scrupulously determine properties of the excited triplet state and compare them with those of the conventional triplet state. Both triplets exhibit similar patterns of anisotropic fine structure and Zeeman splitting, however their amplitudes significantly differ for those two states. Presented results emphasize the role of the symmetry of the electronic state on the properties of the triplet states of two holes + electron excitonic complex.
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Affiliation(s)
- M R Molas
- Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland. Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
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14
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Wallbank JR, Ghazaryan D, Misra A, Cao Y, Tu JS, Piot BA, Potemski M, Pezzini S, Wiedmann S, Zeitler U, Lane TLM, Morozov SV, Greenaway MT, Eaves L, Geim AK, Fal'ko VI, Novoselov KS, Mishchenko A. Tuning the valley and chiral quantum state of Dirac electrons in van der Waals heterostructures. Science 2016; 353:575-9. [DOI: 10.1126/science.aaf4621] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 07/13/2016] [Indexed: 11/02/2022]
Affiliation(s)
- J. R. Wallbank
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - D. Ghazaryan
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - A. Misra
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - Y. Cao
- Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester M13 9PL, UK
| | - J. S. Tu
- Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester M13 9PL, UK
| | - B. A. Piot
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - M. Potemski
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS-UGA-UPS-INSA-EMFL, 25 avenue des Martyrs, 38042 Grenoble, France
| | - S. Pezzini
- High Field Magnet Laboratory (HFML-EMFL) and Institute of Molecules and Materials, Radboud University, Nijmegen, 6525 ED, Netherlands
| | - S. Wiedmann
- High Field Magnet Laboratory (HFML-EMFL) and Institute of Molecules and Materials, Radboud University, Nijmegen, 6525 ED, Netherlands
| | - U. Zeitler
- High Field Magnet Laboratory (HFML-EMFL) and Institute of Molecules and Materials, Radboud University, Nijmegen, 6525 ED, Netherlands
| | - T. L. M. Lane
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - S. V. Morozov
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- Institute of Microelectronics Technology and High Purity Materials, RAS, Chernogolovka 142432, Russia
- National University of Science and Technology “MISiS”, 119049, Leninsky pr. 4, Moscow, Russia
| | - M. T. Greenaway
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - L. Eaves
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - A. K. Geim
- Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester M13 9PL, UK
| | - V. I. Fal'ko
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - K. S. Novoselov
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - A. Mishchenko
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
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15
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Kobak J, Smoleński T, Goryca M, Rousset JG, Pacuski W, Bogucki A, Oreszczuk K, Kossacki P, Nawrocki M, Golnik A, Płachta J, Wojnar P, Kruse C, Hommel D, Potemski M, Kazimierczuk T. Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots. J Phys Condens Matter 2016; 28:265302. [PMID: 27173643 DOI: 10.1088/0953-8984/28/26/265302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X(+), X(-)) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting δ1=0.14 meV (δ1=0.47 meV); g-factor g = 2.12 (g = 1.71); diamagnetic shift γ=2.5 μeV T(-2) (γ =1.3 μeV T(-2)). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.
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Affiliation(s)
- J Kobak
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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16
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Ohnoutek L, Hakl M, Veis M, Piot BA, Faugeras C, Martinez G, Yakushev MV, Martin RW, Drašar Č, Materna A, Strzelecka G, Hruban A, Potemski M, Orlita M. Strong interband Faraday rotation in 3D topological insulator Bi2Se3. Sci Rep 2016; 6:19087. [PMID: 26750455 PMCID: PMC4707504 DOI: 10.1038/srep19087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/02/2015] [Indexed: 11/26/2022] Open
Abstract
The Faraday effect is a representative magneto-optical phenomenon, resulting from the transfer of angular momentum between interacting light and matter in which time-reversal symmetry has been broken by an externally applied magnetic field. Here we report on the Faraday rotation induced in the prominent 3D topological insulator Bi2Se3 due to bulk interband excitations. The origin of this non-resonant effect, extraordinarily strong among other non-magnetic materials, is traced back to the specific Dirac-type Hamiltonian for Bi2Se3, which implies that electrons and holes in this material closely resemble relativistic particles with a non-zero rest mass.
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Affiliation(s)
- L Ohnoutek
- Institute of Physics, Charles University, Ke Karlovu 5, CZ-121 16 Praha 2, Czech Republic
| | - M Hakl
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Veis
- Institute of Physics, Charles University, Ke Karlovu 5, CZ-121 16 Praha 2, Czech Republic
| | - B A Piot
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - G Martinez
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M V Yakushev
- Department of Physics, SUPA, Strathclyde University, G4 0NG Glasgow, UK
- Ural Federal University and Institute of Solid State Chemistry of RAS, Ekaterinburg, 620002, Russia
| | - R W Martin
- Department of Physics, SUPA, Strathclyde University, G4 0NG Glasgow, UK
| | - Č Drašar
- Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentská 84, 532 10 Pardubice, Czech Republic
| | - A Materna
- Institute of Electronic Materials Technology, ul. Wolczynska 133, PL 01-919 Warsaw, Poland
| | - G Strzelecka
- Institute of Electronic Materials Technology, ul. Wolczynska 133, PL 01-919 Warsaw, Poland
| | - A Hruban
- Institute of Electronic Materials Technology, ul. Wolczynska 133, PL 01-919 Warsaw, Poland
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Orlita
- Institute of Physics, Charles University, Ke Karlovu 5, CZ-121 16 Praha 2, Czech Republic
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
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17
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Cao Y, Mishchenko A, Yu GL, Khestanova E, Rooney AP, Prestat E, Kretinin AV, Blake P, Shalom MB, Woods C, Chapman J, Balakrishnan G, Grigorieva IV, Novoselov KS, Piot BA, Potemski M, Watanabe K, Taniguchi T, Haigh SJ, Geim AK, Gorbachev RV. Quality Heterostructures from Two-Dimensional Crystals Unstable in Air by Their Assembly in Inert Atmosphere. Nano Lett 2015; 15:4914-4921. [PMID: 26132110 DOI: 10.1021/acs.nanolett.5b00648] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Many layered materials can be cleaved down to individual atomic planes, similar to graphene, but only a small minority of them are stable under ambient conditions. The rest react and decompose in air, which has severely hindered their investigation and potential applications. Here we introduce a remedial approach based on cleavage, transfer, alignment, and encapsulation of air-sensitive crystals, all inside a controlled inert atmosphere. To illustrate the technology, we choose two archetypal two-dimensional crystals that are of intense scientific interest but are unstable in air: black phosphorus and niobium diselenide. Our field-effect devices made from their monolayers are conductive and fully stable under ambient conditions, which is in contrast to the counterparts processed in air. NbSe2 remains superconducting down to the monolayer thickness. Starting with a trilayer, phosphorene devices reach sufficiently high mobilities to exhibit Landau quantization. The approach offers a venue to significantly expand the range of experimentally accessible two-dimensional crystals and their heterostructures.
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Affiliation(s)
| | | | | | | | | | | | | | - P Blake
- ∥Graphene Industries Ltd., 2 Tupelo Street, Manchester, M13 9HQ, United Kingdom
| | | | | | | | - G Balakrishnan
- ⊥Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | | | | | - B A Piot
- #Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, F-38042 Grenoble, France
| | - M Potemski
- #Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, F-38042 Grenoble, France
| | - K Watanabe
- ∇National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - T Taniguchi
- ∇National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
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18
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Koperski M, Nogajewski K, Arora A, Cherkez V, Mallet P, Veuillen JY, Marcus J, Kossacki P, Potemski M. Single photon emitters in exfoliated WSe2 structures. Nat Nanotechnol 2015; 10:503-6. [PMID: 25938573 DOI: 10.1038/nnano.2015.67] [Citation(s) in RCA: 304] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/12/2015] [Indexed: 05/20/2023]
Abstract
Crystal structure imperfections in solids often act as efficient carrier trapping centres, which, when suitably isolated, act as sources of single photon emission. The best known examples of such attractive imperfections are well-width or composition fluctuations in semiconductor heterostructures (resulting in the formation of quantum dots) and coloured centres in wide-bandgap materials such as diamond. In the recently investigated thin films of layered compounds, the crystal imperfections may logically be expected to appear at the edges of commonly investigated few-layer flakes of these materials exfoliated on alien substrates. Here, we report comprehensive optical micro-spectroscopy studies of thin layers of tungsten diselenide (WSe2), a representative semiconducting dichalcogenide with a bandgap in the visible spectral range. At the edges of WSe2 flakes (transferred onto Si/SiO2 substrates) we discover centres that, at low temperatures, give rise to sharp emission lines (100 μeV linewidth). These narrow emission lines reveal the effect of photon antibunching, the unambiguous attribute of single photon emitters. The optical response of these emitters is inherently linked to the two-dimensional properties of the WSe2 monolayer, as they both give rise to luminescence in the same energy range, have nearly identical excitation spectra and have very similar, characteristically large Zeeman effects. With advances in the structural control of edge imperfections, thin films of WSe2 may provide added functionalities that are relevant for the domain of quantum optoelectronics.
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Affiliation(s)
- M Koperski
- 1] Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 Rue des Martyrs, Grenoble 38042, France [2] Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 Rue des Martyrs, Grenoble 38042, France
| | - A Arora
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 Rue des Martyrs, Grenoble 38042, France
| | - V Cherkez
- Institut Néel, CNRS-UGA, Grenoble 38042, France
| | - P Mallet
- Institut Néel, CNRS-UGA, Grenoble 38042, France
| | | | - J Marcus
- Institut Néel, CNRS-UGA, Grenoble 38042, France
| | - P Kossacki
- 1] Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 Rue des Martyrs, Grenoble 38042, France [2] Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 Rue des Martyrs, Grenoble 38042, France
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19
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Orlita M, Piot BA, Martinez G, Kumar NKS, Faugeras C, Potemski M, Michel C, Hankiewicz EM, Brauner T, Drašar Č, Schreyeck S, Grauer S, Brunner K, Gould C, Brüne C, Molenkamp LW. Magneto-optics of massive dirac fermions in bulk Bi2Se3. Phys Rev Lett 2015; 114:186401. [PMID: 26001011 DOI: 10.1103/physrevlett.114.186401] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Indexed: 05/27/2023]
Abstract
We report on magneto-optical studies of Bi2Se3, a representative member of the 3D topological insulator family. Its electronic states in bulk are shown to be well described by a simple Dirac-type Hamiltonian for massive particles with only two parameters: the fundamental band gap and the band velocity. In a magnetic field, this model implies a unique property-spin splitting equal to twice the cyclotron energy: Es=2Ec. This explains the extensive magnetotransport studies concluding a fortuitous degeneracy of the spin and orbital split Landau levels in this material. The Es=2Ec match differentiates the massive Dirac electrons in bulk Bi2Se3 from those in quantum electrodynamics, for which Es=Ec always holds.
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Affiliation(s)
- M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
- Institute of Physics, Charles University in Prague, CZ-12116 Prague, Czech Republic
| | - B A Piot
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - G Martinez
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - N K Sampath Kumar
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France
| | - C Michel
- Institute for Theoretical Physics, TP IV, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - E M Hankiewicz
- Institute for Theoretical Physics, TP IV, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - T Brauner
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria
| | - Č Drašar
- Faculty of Chemical Technology, University of Pardubice, CZ-53210 Pardubice, Czech Republic
| | - S Schreyeck
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
| | - S Grauer
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
| | - K Brunner
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
| | - C Gould
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
| | - C Brüne
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
| | - L W Molenkamp
- Physikalisches Institut (EP III), Universität Würzburg, D-97074 Würzburg, Germany
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20
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Faugeras C, Berciaud S, Leszczynski P, Henni Y, Nogajewski K, Orlita M, Taniguchi T, Watanabe K, Forsythe C, Kim P, Jalil R, Geim AK, Basko DM, Potemski M. Landau level spectroscopy of electron-electron interactions in graphene. Phys Rev Lett 2015; 114:126804. [PMID: 25860767 DOI: 10.1103/physrevlett.114.126804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Indexed: 06/04/2023]
Abstract
We present magneto-Raman scattering studies of electronic inter-Landau level excitations in quasineutral graphene samples with different strengths of Coulomb interaction. The band velocity associated with these excitations is found to depend on the dielectric environment, on the index of Landau level involved, and to vary as a function of the magnetic field. This contradicts the single-particle picture of noninteracting massless Dirac electrons but is accounted for by theory when the effect of electron-electron interaction is taken into account. Raman active, zero-momentum inter-Landau level excitations in graphene are sensitive to electron-electron interactions due to the nonapplicability of the Kohn theorem in this system, with a clearly nonparabolic dispersion relation.
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Affiliation(s)
- C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - S Berciaud
- Institut de Physique et Chimie des Matériaux de Strasbourg and NIE, UMR 7504, Université de Strasbourg and CNRS, BP43, 67034 Strasbourg, Cedex 2, France
| | - P Leszczynski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - Y Henni
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - K Nogajewski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
| | - T Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - K Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Forsythe
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - P Kim
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - R Jalil
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - D M Basko
- Université Grenoble 1/CNRS, Laboratoire de Physique et de Modélisation des Milieux Condensés (UMR 5493), B.P. 166, 38042 Grenoble, Cedex 9, France
| | - M Potemski
- Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France
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21
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Witowski AM, Sadowski ML, Paku ,a K, Suchanek B, Stepniewski R, Baranowski JM, Potemski M, Martinez G, Wyder P. Magneto-optical studies of shallow donors in MOCVD grown GaN layers in FIR. ACTA ACUST UNITED AC 2014. [DOI: 10.1557/s1092578300001058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Far infrared magnetooptical investigations of shallow donors in epitaxial MOCVD GaN layers show two types of shallow donors. In relaxed layers, a donor with an ionization energy of 35 meV was found. In strained, undoped and Si doped samples, a donor with ionization energy 32.5 meV was observed. From the p state splitting in magnetic field, the cyclotron effective mass for conduction electrons was found to be m*=0.222 m0.
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22
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Ponomarenko LA, Gorbachev RV, Yu GL, Elias DC, Jalil R, Patel AA, Mishchenko A, Mayorov AS, Woods CR, Wallbank JR, Mucha-Kruczynski M, Piot BA, Potemski M, Grigorieva IV, Novoselov KS, Guinea F, Fal'ko VI, Geim AK. Cloning of Dirac fermions in graphene superlattices. Nature 2013; 497:594-7. [PMID: 23676678 DOI: 10.1038/nature12187] [Citation(s) in RCA: 429] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 04/03/2013] [Indexed: 11/09/2022]
Abstract
Superlattices have attracted great interest because their use may make it possible to modify the spectra of two-dimensional electron systems and, ultimately, create materials with tailored electronic properties. In previous studies (see, for example, refs 1-8), it proved difficult to realize superlattices with short periodicities and weak disorder, and most of their observed features could be explained in terms of cyclotron orbits commensurate with the superlattice. Evidence for the formation of superlattice minibands (forming a fractal spectrum known as Hofstadter's butterfly) has been limited to the observation of new low-field oscillations and an internal structure within Landau levels. Here we report transport properties of graphene placed on a boron nitride substrate and accurately aligned along its crystallographic directions. The substrate's moiré potential acts as a superlattice and leads to profound changes in the graphene's electronic spectrum. Second-generation Dirac points appear as pronounced peaks in resistivity, accompanied by reversal of the Hall effect. The latter indicates that the effective sign of the charge carriers changes within graphene's conduction and valence bands. Strong magnetic fields lead to Zak-type cloning of the third generation of Dirac points, which are observed as numerous neutrality points in fields where a unit fraction of the flux quantum pierces the superlattice unit cell. Graphene superlattices such as this one provide a way of studying the rich physics expected in incommensurable quantum systems and illustrate the possibility of controllably modifying the electronic spectra of two-dimensional atomic crystals by varying their crystallographic alignment within van der Waals heterostuctures.
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Affiliation(s)
- L A Ponomarenko
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
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23
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Winnerl S, Göttfert F, Mittendorff M, Schneider H, Helm M, Winzer T, Malic E, Knorr A, Orlita M, Potemski M, Sprinkle M, Berger C, de Heer WA. Time-resolved spectroscopy on epitaxial graphene in the infrared spectral range: relaxation dynamics and saturation behavior. J Phys Condens Matter 2013; 25:054202. [PMID: 23441326 DOI: 10.1088/0953-8984/25/5/054202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We present the results of pump–probe experiments on multilayer graphene samples performed in a wide spectral range, namely from the near infrared (photon energy 1.5 eV) to the terahertz (photon energy 8 meV) spectral range. In the near infrared, exciting carriers and probing at higher photon energies provides direct evidence for a hot carrier distribution. Furthermore, spectroscopic signatures of the highly doped graphene layers at the interface to SiC are observed in the near-infrared range. In the mid-infrared range, the various relaxation mechanisms, in particular scattering via optical phonons and Auger-type processes, are identified by comparing the experimental results to microscopic modeling. Changes from induced transmission to induced absorption are attributed to probing above or below the Fermi edge of the graphene layers. This effect occurs for certain photon energies in the near-infrared range, where it is related to highly doped graphene layers at the interface to SiC, and in the far-infrared range for the quasi-intrinsic graphene layers. In addition to the relaxation dynamics, the saturation of pump-induced bleaching of graphene is studied. Here a quadratic dependence of the saturation fluence on the pump photon energy in the infrared spectral range is revealed.
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Affiliation(s)
- S Winnerl
- Helmholtz-Zentrum Dresden-Rossendorf, PO Box 510119, D-01314 Dresden, Germany.
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24
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Orlita M, Tan LZ, Potemski M, Sprinkle M, Berger C, de Heer WA, Louie SG, Martinez G. Resonant excitation of graphene k-phonon and intra-landau-level excitons in magneto-optical spectroscopy [corrected]. Phys Rev Lett 2012; 108:247401. [PMID: 23004329 DOI: 10.1103/physrevlett.108.247401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Indexed: 06/01/2023]
Abstract
Precise infrared magnetotransmission experiments have been performed in magnetic fields up to 32 T on a series of multilayer epitaxial graphene samples. We observe changes in the spectral features and broadening of the main cyclotron transition when the incoming photon energy is in resonance with the lowest Landau level separation and the energy of a K point optical phonon. We have developed a theory that explains and quantitatively reproduces the frequency and magnetic field dependence of the phenomenon as the absorption of a photon together with the simultaneous creation of an intervalley, intra-Landau-level exciton, and a K phonon.
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Affiliation(s)
- M Orlita
- Laboratoire National des Champs Magntiques Intenses, CNRS-UJF-UPS-INSA, B.P. 166, 38042 Grenoble Cedex 9, France
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25
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Crassee I, Orlita M, Potemski M, Walter AL, Ostler M, Seyller T, Gaponenko I, Chen J, Kuzmenko AB. Intrinsic terahertz plasmons and magnetoplasmons in large scale monolayer graphene. Nano Lett 2012; 12:2470-2474. [PMID: 22519967 DOI: 10.1021/nl300572y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We show that in graphene epitaxially grown on SiC the Drude absorption is transformed into a strong terahertz plasmonic peak due to natural nanoscale inhomogeneities, such as substrate terraces and wrinkles. The excitation of the plasmon modifies dramatically the magneto-optical response and in particular the Faraday rotation. This makes graphene a unique playground for plasmon-controlled magneto-optical phenomena thanks to a cyclotron mass 2 orders of magnitude smaller than in conventional plasmonic materials such as noble metals.
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Affiliation(s)
- I Crassee
- Département de Physique de la Matière Condensée, Université de Genève, 1211 Genève, Switzerland.
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26
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Orlita M, Neugebauer P, Faugeras C, Barra AL, Potemski M, Pellegrino FMD, Basko DM. Cyclotron motion in the vicinity of a Lifshitz transition in graphite. Phys Rev Lett 2012; 108:017602. [PMID: 22304291 DOI: 10.1103/physrevlett.108.017602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Indexed: 05/31/2023]
Abstract
Graphite, a model (semi)metal with trigonally warped bands, is investigated with a magnetoabsorption experiment and viewed as an electronic system in the vicinity of the Lifshitz transition. A characteristic pattern of up to 20 cyclotron resonance harmonics has been observed. This large number of resonances, their relative strengths and characteristic shapes trace the universal properties of the electronic states near a separatrix in momentum space. Quantum-mechanical perturbative methods with respect to the trigonal warping term hardly describe the data which are, on the other hand, fairly well reproduced within a quasiclassical approach and conventional band structure model. Trigonal symmetry is preserved in graphite in contrast to a similar system, bilayer graphene.
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Affiliation(s)
- M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, Grenoble, France
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27
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Winnerl S, Orlita M, Plochocka P, Kossacki P, Potemski M, Winzer T, Malic E, Knorr A, Sprinkle M, Berger C, de Heer WA, Schneider H, Helm M. Carrier relaxation in epitaxial graphene photoexcited near the Dirac point. Phys Rev Lett 2011; 107:237401. [PMID: 22182122 DOI: 10.1103/physrevlett.107.237401] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Indexed: 05/31/2023]
Abstract
We study the carrier dynamics in epitaxially grown graphene in the range of photon energies from 10 to 250 meV. The experiments complemented by microscopic modeling reveal that the carrier relaxation is significantly slowed down as the photon energy is tuned to values below the optical-phonon frequency; however, owing to the presence of hot carriers, optical-phonon emission is still the predominant relaxation process. For photon energies about twice the value of the Fermi energy, a transition from pump-induced transmission to pump-induced absorption occurs due to the interplay of interband and intraband processes.
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Affiliation(s)
- S Winnerl
- Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
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28
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Orlita M, Faugeras C, Grill R, Wysmolek A, Strupinski W, Berger C, de Heer WA, Martinez G, Potemski M. Carrier scattering from dynamical magnetoconductivity in quasineutral epitaxial graphene. Phys Rev Lett 2011; 107:216603. [PMID: 22181904 DOI: 10.1103/physrevlett.107.216603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Indexed: 05/31/2023]
Abstract
The energy dependence of the electronic scattering time is probed by Landau level spectroscopy in quasineutral multilayer epitaxial graphene. From the broadening of overlapping Landau levels we find that the scattering rate 1/τ increases linearly with energy ϵ. This implies a surprising property of the Landau level spectrum in graphene-the number of resolved Landau levels remains constant with the applied magnetic field. Insights are given about possible scattering mechanisms and carrier mobilities in the graphene system investigated.
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Affiliation(s)
- M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, Grenoble, France.
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29
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Trojnar AH, Korkusiński M, Kadantsev ES, Hawrylak P, Goryca M, Kazimierczuk T, Kossacki P, Wojnar P, Potemski M. Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dot. Phys Rev Lett 2011; 107:207403. [PMID: 22181774 DOI: 10.1103/physrevlett.107.207403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Indexed: 05/31/2023]
Abstract
We show theoretically and experimentally the existence of a new quantum-interference effect between the electron-hole interactions and the scattering by a single Mn impurity. The theoretical model, including electron-valence-hole correlations, the short- and long-range exchange interaction of a Mn ion with the heavy hole and with electron and anisotropy of the quantum dot, is compared with photoluminescence spectroscopy of CdTe dots with single magnetic ions. We show how the design of the electronic levels of a quantum dot enables the design of an exciton, control of the quantum interference, and hence engineering of light-Mn interaction.
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Affiliation(s)
- A H Trojnar
- Institute for Microstructural Sciences, National Research Council, Ottawa, Canada
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30
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Faugeras C, Amado M, Kossacki P, Orlita M, Kühne M, Nicolet AAL, Latyshev YI, Potemski M. Magneto-Raman scattering of graphene on graphite: electronic and phonon excitations. Phys Rev Lett 2011; 107:036807. [PMID: 21838392 DOI: 10.1103/physrevlett.107.036807] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Indexed: 05/31/2023]
Abstract
Magneto-Raman-scattering experiments from the surface of graphite reveal novel features associated to purely electronic excitations which are observed in addition to phonon-mediated resonances. Graphene-like and graphite domains are identified through experiments with ∼1 μm spatial resolution performed in magnetic fields up to 32 T. Polarization resolved measurements emphasize the characteristic selection rules for electronic transitions in graphene. Graphene on graphite displays the unexpected hybridization between optical phonon and symmetric across the Dirac point inter Landau level transitions. The results open new experimental possibilities--to use light scattering methods in studies of graphene under quantum Hall effect conditions.
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Affiliation(s)
- C Faugeras
- LNCMI, UPR 3228, CNRS-UJF-UPS-INSA, 38042 Grenoble, France
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31
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Stern M, Plochocka P, Umansky V, Maude DK, Potemski M, Bar-Joseph I. Optical probing of the spin polarization of the ν=5/2 quantum Hall state. Phys Rev Lett 2010; 105:096801. [PMID: 20868182 DOI: 10.1103/physrevlett.105.096801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Indexed: 05/29/2023]
Abstract
We apply polarization resolved photoluminescence spectroscopy to measure the spin polarization of a two dimensional electron gas in perpendicular magnetic field. We find that the splitting between the σ+ and σ- polarizations exhibits a sharp drop at ν=5/2 and is equal to the bare Zeeman energy, which resembles the behavior at even filling factors. We show that this behavior is consistent with filling factor ν=5/2 being unpolarized.
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Affiliation(s)
- M Stern
- Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot, Israel.
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32
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Faugeras C, Faugeras B, Orlita M, Potemski M, Nair RR, Geim AK. Thermal conductivity of graphene in corbino membrane geometry. ACS Nano 2010; 4:1889-1892. [PMID: 20218666 DOI: 10.1021/nn9016229] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Local laser excitation and temperature readout from the intensity ratio of Stokes to anti-Stokes Raman scattering signals are employed to study the thermal properties of a large graphene membrane. The concluded value of the heat conductivity coefficient kappa approximately 600 W/(m.K) is smaller than previously reported but still validates the conclusion that graphene is a very good thermal conductor.
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Affiliation(s)
- Clement Faugeras
- Laboratoire National des Champs Magnetiques Intenses, CNRS-UJF-UPS-INSA, 25 Avenue des Martyrs, 38042 Grenoble, France.
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33
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Faugeras C, Amado M, Kossacki P, Orlita M, Sprinkle M, Berger C, de Heer WA, Potemski M. Tuning the electron-phonon coupling in multilayer graphene with magnetic fields. Phys Rev Lett 2009; 103:186803. [PMID: 19905824 DOI: 10.1103/physrevlett.103.186803] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Indexed: 05/28/2023]
Abstract
Magneto-Raman scattering study of the E2g optical phonons in multilayer epitaxial graphene grown on a carbon face of SiC is presented. At 4.2 K in magnetic field up to 33 T, we observe a series of well-pronounced avoided crossings each time the optically active inter-Landau level transition is tuned in resonance with the E2g phonon excitation (at 196 meV). The width of the phonon Raman scattering response also shows pronounced variations and is enhanced in conditions of resonance. The experimental results are well reproduced by a model that gives directly the strength of the electron-phonon interaction.
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Affiliation(s)
- C Faugeras
- LNCMI-CNRS, BP 166, 38042 Grenoble Cedex 9, France
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34
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Neugebauer P, Orlita M, Faugeras C, Barra AL, Potemski M. How perfect can graphene be? Phys Rev Lett 2009. [PMID: 19905531 DOI: 10.1103/physrevlett.103.159902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We have identified the cyclotron resonance response of the purest graphene ever investigated, which can be found in nature on the surface of bulk graphite, in the form of decoupled layers from the substrate material. Probing such flakes with Landau level spectroscopy in the THz range at very low magnetic fields, we demonstrate a superior electronic quality of these ultralow density layers (n_{0} approximately 3 x 10;{9} cm;{-2}) expressed by the carrier mobility in excess of 10;{7} cm;{2}/(V * s) or scattering time of tau approximately 20 ps. These parameters set new and surprisingly high limits for intrinsic properties of graphene and represent an important challenge for further developments of current graphene technologies.
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Affiliation(s)
- P Neugebauer
- Grenoble High Magnetic Field Laboratory, CNRS, BP 166, F-38042 Grenoble Cedex 09, France
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35
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Abstract
We have identified the cyclotron resonance response of the purest graphene ever investigated, which can be found in nature on the surface of bulk graphite, in the form of decoupled layers from the substrate material. Probing such flakes with Landau level spectroscopy in the THz range at very low magnetic fields, we demonstrate a superior electronic quality of these ultralow density layers (n_{0} approximately 3 x 10;{9} cm;{-2}) expressed by the carrier mobility in excess of 10;{7} cm;{2}/(V * s) or scattering time of tau approximately 20 ps. These parameters set new and surprisingly high limits for intrinsic properties of graphene and represent an important challenge for further developments of current graphene technologies.
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Affiliation(s)
- P Neugebauer
- Grenoble High Magnetic Field Laboratory, CNRS, BP 166, F-38042 Grenoble Cedex 09, France
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36
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Orlita M, Faugeras C, Schneider JM, Martinez G, Maude DK, Potemski M. Graphite from the viewpoint of Landau level spectroscopy: an effective graphene bilayer and monolayer. Phys Rev Lett 2009; 102:166401. [PMID: 19518730 DOI: 10.1103/physrevlett.102.166401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Indexed: 05/27/2023]
Abstract
We describe an infrared transmission study of a thin layer of bulk graphite in magnetic fields up to B=34 T. Two series of absorption lines whose energy scales as sqrt[B] and B are present in the spectra and identified as contributions of massless holes at the H point and massive electrons in the vicinity of the K point, respectively. We find that the optical response of the K point electrons corresponds, over a wide range of energy and magnetic field, to a graphene bilayer with an effective interlayer coupling 2gamma_{1}, twice the value for a real graphene bilayer, which reflects the crystal ordering of bulk graphite along the c axis. The K point electrons thus behave as massive Dirac fermions with a mass enhanced twice in comparison to a true graphene bilayer.
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Affiliation(s)
- M Orlita
- Laboratoire National des Champs Magnétiques Intenses, CNRS, BP 166, F-38042 Grenoble Cedex 09, France.
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37
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Schneider JM, Orlita M, Potemski M, Maude DK. Consistent interpretation of the low-temperature magnetotransport in graphite using the Slonczewski-Weiss-McClure 3D band-structure calculations. Phys Rev Lett 2009; 102:166403. [PMID: 19518732 DOI: 10.1103/physrevlett.102.166403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Indexed: 05/27/2023]
Abstract
Magnetotransport of natural graphite and highly oriented pyrolytic graphite has been measured at mK temperatures. Quantum oscillations for both electron and hole carriers are observed with an orbital angular momentum quantum number up to N approximately 90. A remarkable agreement is obtained when comparing the data and the predictions of the Slonczewski-Weiss-McClure tight binding model for massive fermions. No evidence for Dirac fermions is observed in the transport data which are dominated by the crossing of the Landau bands at the Fermi level, corresponding to dE/dk_{z}=0, which occurs away from the H point where Dirac fermions are expected.
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Affiliation(s)
- J M Schneider
- Grenoble High Magnetic Field Laboratory, CNRS, 38042 Grenoble, France.
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38
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Plochocka P, Schneider JM, Maude DK, Potemski M, Rappaport M, Umansky V, Bar-Joseph I, Groshaus JG, Gallais Y, Pinczuk A. Optical absorption to probe the quantum Hall ferromagnet at filling factor nu=1. Phys Rev Lett 2009; 102:126806. [PMID: 19392309 DOI: 10.1103/physrevlett.102.126806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Indexed: 05/27/2023]
Abstract
Optical absorption measurements are used to probe the spin polarization in the integer and fractional quantum Hall effect regimes. The system is fully spin polarized only at filling factor nu=1 and at very low temperatures ( approximately 40 mK). A small change in filling factor (deltanu approximately +/-0.01) leads to a significant depolarization. This suggests that the itinerant quantum Hall ferromagnet at nu=1 is surprisingly fragile against increasing temperature, or against small changes in filling factor.
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Affiliation(s)
- P Plochocka
- Laboratoire National des Champs Magnétiques Intenses, Grenoble High Magnetic Field Laboratory, 38042 Grenoble, France.
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Orlita M, Faugeras C, Plochocka P, Neugebauer P, Martinez G, Maude DK, Barra AL, Sprinkle M, Berger C, de Heer WA, Potemski M. Approaching the dirac point in high-mobility multilayer epitaxial graphene. Phys Rev Lett 2008; 101:267601. [PMID: 19437673 DOI: 10.1103/physrevlett.101.267601] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Multilayer epitaxial graphene is investigated using far infrared transmission experiments in the different limits of low magnetic fields and high temperatures. The cyclotron-resonance-like absorption is observed at low temperature in magnetic fields below 50 mT, probing the nearest vicinity of the Dirac point. The carrier mobility is found to exceed 250,000 cm2/(V x s). In the limit of high temperatures, the well-defined Landau level quantization is observed up to room temperature at magnetic fields below 1 T, a phenomenon unusual in solid state systems. A negligible increase in the width of the cyclotron resonance lines with increasing temperature indicates that no important scattering mechanism is thermally activated.
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Affiliation(s)
- M Orlita
- Grenoble High Magnetic Field Laboratory, CNRS, BP 166, F-38042 Grenoble Cedex 09, France.
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Orlita M, Faugeras C, Martinez G, Maude DK, Sadowski ML, Potemski M. Dirac fermions at the H point of graphite: magnetotransmission studies. Phys Rev Lett 2008; 100:136403. [PMID: 18517976 DOI: 10.1103/physrevlett.100.136403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Indexed: 05/26/2023]
Abstract
We report on far infrared magnetotransmission measurements on a thin graphite sample prepared by exfoliation of highly oriented pyrolytic graphite. In a magnetic field, absorption lines exhibiting a blueshift proportional to sqrt[B] are observed. This is a fingerprint for massless Dirac holes at the H point in bulk graphite. The Fermi velocity is found to be c[over ] =( 1.02+/-0.02) x 10(6) m/s and the pseudogap |Delta| at the H point is estimated to be below 10 meV. Although the holes behave to a first approximation as a strictly 2D gas of Dirac fermions, the full 3D band structure has to be taken into account to explain all the observed spectral features.
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Affiliation(s)
- M Orlita
- Grenoble High Magnetic Field Laboratory, CNRS, BP 166, F-38042 Grenoble Cedex 09, France.
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41
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Plochocka P, Faugeras C, Orlita M, Sadowski ML, Martinez G, Potemski M, Goerbig MO, Fuchs JN, Berger C, de Heer WA. High-energy limit of massless Dirac fermions in multilayer graphene using magneto-optical transmission spectroscopy. Phys Rev Lett 2008; 100:087401. [PMID: 18352662 DOI: 10.1103/physrevlett.100.087401] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2007] [Revised: 11/15/2007] [Indexed: 05/26/2023]
Abstract
We have investigated the absorption spectrum of multilayer graphene in high magnetic fields. The low-energy part of the spectrum of electrons in graphene is well described by the relativistic Dirac equation with a linear dispersion relation. However, at higher energies (>500 meV) a deviation from the ideal behavior of Dirac particles is observed. At an energy of 1.25 eV, the deviation from linearity is approximately 40 meV. This result is in good agreement with the theoretical model, which includes trigonal warping of the Fermi surface and higher-order band corrections. Polarization-resolved measurements show no observable electron-hole asymmetry.
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Affiliation(s)
- P Plochocka
- Grenoble High Magnetic Field Laboratory, CNRS, 38042 Grenoble, France.
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42
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Sadowski ML, Martinez G, Potemski M, Berger C, de Heer WA. Landau level spectroscopy of ultrathin graphite layers. Phys Rev Lett 2006; 97:266405. [PMID: 17280440 DOI: 10.1103/physrevlett.97.266405] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Indexed: 05/13/2023]
Abstract
Far infrared transmission experiments are performed on ultrathin epitaxial graphite samples in a magnetic field. The observed cyclotron resonance-like and electron-positron-like transitions are in excellent agreement with the expectations of a single-particle model of Dirac fermions in graphene, with an effective velocity of c=1.03 x 10(6) m/s.
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Affiliation(s)
- M L Sadowski
- Grenoble High Magnetic Field Laboratory, CNRS, Grenoble, France
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43
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Raymond S, Studenikin S, Sachrajda A, Wasilewski Z, Cheng SJ, Sheng W, Hawrylak P, Babinski A, Potemski M, Ortner G, Bayer M. Excitonic energy shell structure of self-assembled InGaAs/GaAs quantum dots. Phys Rev Lett 2004; 92:187402. [PMID: 15169530 DOI: 10.1103/physrevlett.92.187402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Indexed: 05/24/2023]
Abstract
Performing optical spectroscopy of highly homogeneous quantum dot arrays in ultrahigh magnetic fields, an unprecedently well resolved Fock-Darwin spectrum is observed. The existence of up to four degenerate electronic shells is demonstrated where the magnetic field lifts the initial degeneracies, which reappear when levels with different angular momenta come into resonance. The resulting level shifting and crossing pattern also show evidence of many-body effects such as the mixing of configurations and exciton condensation at the resonances.
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Affiliation(s)
- S Raymond
- Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
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St?pniewski R, Wysmo?ek A, Potemski M. Electronic structure of shallow impurities in GaN studied via bound exciton magnetooptics. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pssa.200303908] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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Stepniewski R, Wysmołek A, Potemski M, Pakuła K, Baranowski JM, Grzegory I, Porowski S, Martinez G, Wyder P. Fine structure of effective mass acceptors in gallium nitride. Phys Rev Lett 2003; 91:226404. [PMID: 14683260 DOI: 10.1103/physrevlett.91.226404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2002] [Indexed: 05/24/2023]
Abstract
Magnetoluminescence of the exciton bound to a neutral acceptor was measured to investigate the electronic structure of a shallow acceptor center in GaN. The application of magnetic fields along different directions with respect to the crystal c axis allowed us to determine the symmetry of the ground (Gamma(9)) and the first excited state (Gamma(7)) of the acceptor. The observed Zeeman splitting pattern has axial symmetry but can be explained well only by assuming a significant reduction of the spin-orbit interaction for this acceptor state. Because of this reduction, the energy structure of the neutral acceptor is found to be very sensitive to any local, axial perturbation.
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Affiliation(s)
- R Stepniewski
- Institute of Experimental Physics, Warsaw University, Hoza 69, PL-00-681 Warsaw, Poland
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47
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Teran FJ, Potemski M, Maude DK, Plantier D, Hassan AK, Sachrajda A, Wilamowski Z, Jaroszynski J, Wojtowicz T, Karczewski G. Collective character of spin excitations in a system of Mn2+ spins coupled to a two-dimensional electron gas. Phys Rev Lett 2003; 91:077201. [PMID: 12935049 DOI: 10.1103/physrevlett.91.077201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2002] [Indexed: 05/24/2023]
Abstract
We have studied the low energy spin excitations in n-type CdMnTe based dilute magnetic semiconductor quantum wells. For magnetic fields for which the energies for the excitation of free carriers and Mn spins are almost identical, an anomalously large Knight shift is observed. Our findings suggest the existence of a magnetic-field-induced ferromagnetic order in these structures, which is in agreement with recent theoretical predictions [Phys. Rev. Lett. 91, 077202 (2003)]].
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Affiliation(s)
- F J Teran
- Grenoble High Magnetic Field Laboratory, Max Planck Institut für Festkörperforschung and Centre National de la Recherche Scientifique, B.P. 166, 38042 Grenoble Cedex 9, France
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48
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Desrat W, Maude DK, Potemski M, Portal JC, Wasilewski ZR, Hill G. Resistively detected nuclear magnetic resonance in the quantum hall regime: possible evidence for a Skyrme crystal. Phys Rev Lett 2002; 88:256807. [PMID: 12097116 DOI: 10.1103/physrevlett.88.256807] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2002] [Indexed: 05/23/2023]
Abstract
Resistively detected nuclear magnetic resonance measurements have been performed on a high mobility heterostructure in the quantum Hall regime. At millikelvin temperatures the nuclear resonances are observed in the vicinity of various integer and fractional filling factors without previous dynamic nuclear polarization. Near nu = 1, the observed large enhancement of the resonance amplitude accompanied by a reduction of T1 strongly suggests a greatly increased coupling between the electronic and nuclear spin systems. This is consistent with the proposed coupling of the nuclear spin system to the Goldstone mode of the Skyrme crystal.
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Affiliation(s)
- W Desrat
- Grenoble High Magnetic Field Laboratory, Max Planck Institut für Festkörperforschung and Centre National de la Recherche Scientifique, BP 166, 38042 Grenoble Cedex 9, France
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Teran FJ, Potemski M, Maude DK, Andrearczyk T, Jaroszynski J, Karczewski G. Pauli paramagnetism and Landau level crossing in a modulation doped CdMnTe/CdMgTe quantum well. Phys Rev Lett 2002; 88:186803. [PMID: 12005710 DOI: 10.1103/physrevlett.88.186803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2002] [Indexed: 05/23/2023]
Abstract
Electrical transport measurements are reported on a 2DEG in a CdMnTe quantum well structure. The amplitude of the Shubnikov-de Haas oscillations show a distinct beating pattern with nodes corresponding to coincidences between the spin splitting and a half integer multiple of the cyclotron energy. The observed pattern of nodes is a direct consequence of the large Pauli paramagnetism induced by the s-d exchange interaction between the spins of electronic states and the localized magnetic moments.
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Affiliation(s)
- F J Teran
- Grenoble High Magnetic Field Laboratory, Max Planck Institut für Festkörperforschung and Centre National de la Recherche Scientifique, BP 166, 38042 Grenoble Cedex 9, France
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Poulter AJ, Zeman J, Maude DK, Potemski M, Martinez G, Riedel A, Hey R, Friedland KJ. Magneto infrared absorption in high electron density GaAs quantum wells. Phys Rev Lett 2001; 86:336-339. [PMID: 11177825 DOI: 10.1103/physrevlett.86.336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2000] [Indexed: 05/23/2023]
Abstract
Magneto infrared absorption measurements have been performed in a highly doped GaAs quantum well which has been lifted off and bonded to a silicon substrate, in order to study the resonant polaron interaction. It is found that the pinning of the cyclotron energy occurs at an energy close to that of the transverse optical phonon of GaAs. This unexpected result is explained by a model taking into account the full dielectric constant of the quantum well.
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Affiliation(s)
- A J Poulter
- Grenoble High Magnetic Field Laboratory MPI-FKF/CNRS, 25 Avenue des Martyrs, F-38042 Grenoble Cedex 9, France
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