1
|
Aragón FFH, Villegas-Lelovsky L, Cabral L, Lima MP, Aquino JCR, Mathpal MC, Coaquira JAH, da Silva SW, Nagamine LCCM, Parreiras SO, Gastelois PL, Marques GE, Macedo WAA. Tailoring the physical and chemical properties of Sn 1-xCo xO 2 nanoparticles: an experimental and theoretical approach. Phys Chem Chem Phys 2020; 22:3702-3714. [PMID: 32003381 DOI: 10.1039/c9cp05928h] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we present a coupled experimental and theoretical first-principles investigation on one of the more promising oxide-diluted magnetic semiconductors, the Sn1-xCoxO2 nanoparticle system, in order to see the effect of cobalt doping on the physical and chemical properties. Our findings suggest that progressive surface enrichment with dopant ions plays an essential role in the monotonous quenching of the surface disorder modes. That weakening is associated with the passivation of the oxygen vacancies as the Co excess at the surface becomes larger. Room-temperature 119Sn Mössbauer spectroscopy data analysis revealed the occurrence of a distribution of isomer shifts, related to the different non-equivalent surroundings of Sn4+ ions and the coexistence of Sn2+/Sn4+ at the particle surfaces provoked by the inhomogeneous distribution of Co ions, in agreement with the X-ray photoelectron spectroscopy measurements. Magnetic measurements revealed a paramagnetic behavior of the Co ions dispersed in the rutile-type matrix with antiferromagnetic correlations, which become stronger as the Co content is increased. Theoretical calculations show that a defect with two Co mediated by a nearby oxygen vacancy is the most likely defect. The predicted effects of this defect complex are in accordance with the experimental results.
Collapse
Affiliation(s)
- F F H Aragón
- Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910900, Brazil. and Laboratorio de Películas Delgadas, Escuela Profesional de Física, Universidad Nacional de San Agustín de Arequipa, Av. Independencia s/n, Arequipa, Peru
| | - L Villegas-Lelovsky
- Departamento de Física, IGCE, Universidade Estadual Paulista, 13506-900 Rio Claro SP, Brazil and Departamento de Física, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil
| | - L Cabral
- Departamento de Física, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil
| | - M P Lima
- Departamento de Física, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil
| | - J C R Aquino
- Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910900, Brazil. and Laboratorio de Películas Delgadas, Escuela Profesional de Física, Universidad Nacional de San Agustín de Arequipa, Av. Independencia s/n, Arequipa, Peru
| | - M C Mathpal
- Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910900, Brazil.
| | - J A H Coaquira
- Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910900, Brazil.
| | - S W da Silva
- Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910900, Brazil.
| | - L C C M Nagamine
- Instituto de Física, Universidade de São Paulo, 05508-090, São Paulo, Brazil
| | - S O Parreiras
- Centro de Desenvolvimento da Tecnologia Nuclear-CDTN, 3127-901, Belo Horizonte, MG, Brazil
| | - P L Gastelois
- Centro de Desenvolvimento da Tecnologia Nuclear-CDTN, 3127-901, Belo Horizonte, MG, Brazil
| | - G E Marques
- Instituto de Física, Universidade de São Paulo, 05508-090, São Paulo, Brazil
| | - W A A Macedo
- Centro de Desenvolvimento da Tecnologia Nuclear-CDTN, 3127-901, Belo Horizonte, MG, Brazil
| |
Collapse
|
2
|
Montero-Muñoz M, Ramos-Ibarra JE, Rodríguez-Páez JE, Marques GE, Teodoro MD, Coaquira JAH. Growth and formation mechanism of shape-selective preparation of ZnO structures: correlation of structural, vibrational and optical properties. Phys Chem Chem Phys 2020; 22:7329-7339. [DOI: 10.1039/c9cp06744b] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A shape-selective preparation method was used to obtain highly crystalline rod-, needle-, nut-, and doughnut-like ZnO morphologies with distinct particle sizes and surface areas.
Collapse
Affiliation(s)
- M. Montero-Muñoz
- Institute of Physics
- University of Brasília
- 70910-900 Brasília-DF
- Brazil
| | - J. E. Ramos-Ibarra
- Institute of Physics
- University of Brasília
- 70910-900 Brasília-DF
- Brazil
- University Center Estácio Brasília
| | | | - G. E. Marques
- Department of Physics
- Federal University of São Carlos
- 13565-905 São Carlos-SP
- Brazil
| | - M. D. Teodoro
- Department of Physics
- Federal University of São Carlos
- 13565-905 São Carlos-SP
- Brazil
| | - J. A. H. Coaquira
- Institute of Physics
- University of Brasília
- 70910-900 Brasília-DF
- Brazil
| |
Collapse
|
3
|
Trallero-Giner C, Padilha JX, Lopez-Richard V, Marques GE, Castelano LK. Quantum well electronic states in a tilted magnetic field. J Phys Condens Matter 2017; 29:325503. [PMID: 28613209 DOI: 10.1088/1361-648x/aa798c] [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: 06/07/2023]
Abstract
We report the energy spectrum and the eigenstates of conduction and uncoupled valence bands of a quantum well under the influence of a tilted magnetic field. In the framework of the envelope approximation, we implement two analytical approaches to obtain the nontrivial solutions of the tilted magnetic field: (a) the Bubnov-Galerkin spectral method and b) the perturbation theory. We discuss the validity of each method for a broad range of magnetic field intensity and orientation as well as quantum well thickness. By estimating the accuracy of the perturbation method, we provide explicit analytical solutions for quantum wells in a tilted magnetic field configuration that can be employed to study several quantitative phenomena.
Collapse
Affiliation(s)
- C Trallero-Giner
- Department of Theoretical Physics, Havana University, Havana 10400, Cuba
| | | | | | | | | |
Collapse
|
4
|
Hartmann F, Maier P, Rebello Sousa Dias M, Göpfert S, Castelano LK, Emmerling M, Schneider C, Höfling S, Kamp M, Pershin YV, Marques GE, Lopez-Richard V, Worschech L. Nanoscale Tipping Bucket Effect in a Quantum Dot Transistor-Based Counter. Nano Lett 2017; 17:2273-2279. [PMID: 28296417 DOI: 10.1021/acs.nanolett.6b04911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electronic circuits composed of one or more elements with inherent memory, that is, memristors, memcapacitors, and meminductors, offer lower circuit complexity and enhanced functionality for certain computational tasks. Networks of these elements are proposed for novel computational paradigms that rely on information processing and storage on the same physical platform. We show a nanoscaled memdevice able to act as an electronic analogue of tipping buckets that allows reducing the dimensionality and complexity of a sensing problem by transforming it into a counting problem. The device offers a well adjustable, tunable, and reliable periodic reset that is controlled by the amounts of transferred quantum dot charges per gate voltage sweep. When subjected to periodic voltage sweeps, the quantum dot (bucket) may require up to several sweeps before a rapid full discharge occurs thus displaying period doubling, period tripling, and so on between self-governing reset operations.
Collapse
Affiliation(s)
- F Hartmann
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - P Maier
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - M Rebello Sousa Dias
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| | - S Göpfert
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - L K Castelano
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - M Emmerling
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - C Schneider
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - S Höfling
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
- SUPA, School of Physics and Astronomy, University of St. Andrews , St. Andrews, KY16 9SS, United Kingdom
| | - M Kamp
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - Y V Pershin
- Department of Physics and Astronomy, University of South Carolina , Columbia, South Carolina 29208, United States
| | - G E Marques
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - V Lopez-Richard
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - L Worschech
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| |
Collapse
|
5
|
Kamimura H, Gouveia RC, Carrocine SC, Souza LD, Rodrigues AD, Teodoro MD, Marques GE, Leite ER, Chiquito AJ. Optical and transport properties correlation driven by amorphous/crystalline disorder in InP nanowires. J Phys Condens Matter 2016; 28:475303. [PMID: 27662434 DOI: 10.1088/0953-8984/28/47/475303] [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
Indium phosphide nanowires with a single crystalline zinc-blend core and polycrystalline/amorphous shell were grown from a reliable route without the use of hazardous precursors. The nanowires are composed by a crystalline core covered by a polycrystalline shell, presenting typical lengths larger than 10 μm and diameters of 80-90 nm. Raman spectra taken from as-grown nanowires exhibited asymmetric line shapes with broadening towards higher wave numbers which can be attributed to phonon localization effects. It was found that optical phonons in the nanowires are localized in regions with average size of 3 nm, which seems to have the same order of magnitude of grain sizes in the polycrystalline shell. Regardless of the fact that the nanowires exhibit a crystalline core, any considerable degree of disorder can lead to a localized behaviour of carriers. In consequence, the variable range hopping was observed as the main transport instead of the usual thermal excitation mechanisms. Furthermore the hopping length was ten times smaller than nanowire cross-sections, confirming that the nanostructures do behave as a 3D system. Accordingly, the V-shape observed in PL spectra clearly demonstrates a very strong influence of the potential fluctuations on the exciton optical recombination. Such fluctuations can still be observed at low temperature regime, confirming that the amorphous/polycrystalline shell of the nanowires affects the exciton recombination in every laser power regime tested.
Collapse
Affiliation(s)
- H Kamimura
- Departamento de Física, Universidade Federal de São Carlos, CEP 13565-905, CP 676, São Carlos, São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
dos Santos LF, Castelano LK, Padilha JX, Pusep Y, Marques GE, Smirnov D, Bakarov AK, Toropov AI, Lopez-Richard V. Excitonic spin-splitting in quantum wells with a tilted magnetic field. J Phys Condens Matter 2016; 28:055503. [PMID: 26766872 DOI: 10.1088/0953-8984/28/5/055503] [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] [Indexed: 06/05/2023]
Abstract
This work aims to investigate the effects of magnetic field strength and direction on the electronic properties and optical response of GaAs/AlGaAs-based heterostructures. An investigation of the excitonic spin-splitting of a disordered multiple quantum well embedded in a wide parabolic quantum well is presented. The results for polarization-resolved photoluminescence show that the magnetic field dependencies of the excitonic spin-splitting and photoluminescence linewidth are crucially sensitive to magnetic field orientation. Our experimental results are in good agreement with the calculated Zeeman splitting obtained by the Luttinger model, which predicts a hybridization of the spin character of states in the valence band under tilted magnetic fields.
Collapse
|
7
|
Mazur YI, Dorogan VG, de Souza LD, Fan D, Benamara M, Schmidbauer M, Ware ME, Tarasov GG, Yu SQ, Marques GE, Salamo GJ. Effects of AlGaAs cladding layers on the luminescence of GaAs/GaAs1-xBix/GaAs heterostructures. Nanotechnology 2014; 25:035702. [PMID: 24346504 DOI: 10.1088/0957-4484/25/3/035702] [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: 06/03/2023]
Abstract
The structural and optical properties of GaAs1-xBix quantum wells (QWs) symmetrically clad by GaAs barriers with and without additional confining AlGaAs layers are studied. It is shown that a GaAs/GaAs1-xBix/GaAs QW with x ~ 4% and well width of ~ 4 nm grown by molecular beam epitaxy demonstrates efficient photoluminescence (PL) that becomes significantly more thermally stable when a cladding AlGaAs layer is added to the QW structure. The PL behavior for temperatures between 10 and 300 K and for excitation intensities varying by seven orders of magnitude can be well described in terms of the dynamics of excitons including carrier capture in the QW layer, thermal emission and diffusion into the cladding barriers. Understanding the role of these processes in the luminescence of dilute GaAs1-xBix QW structures facilitates the creation of highly efficient devices with reduced thermal sensitivity and low threshold current.
Collapse
Affiliation(s)
- Yu I Mazur
- Institute for Nanoscience and Engineering, University of Arkansas, 731 W Dickson Street, Fayetteville, AR 72701, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Freitas Neto ES, Dantas NO, da Silva SW, Morais PC, Pereira-da-Silva MA, Moreno AJD, López-Richard V, Marques GE, Trallero-Giner C. Temperature-dependent Raman study of thermal parameters in CdS quantum dots. Nanotechnology 2012; 23:125701. [PMID: 22397807 DOI: 10.1088/0957-4484/23/12/125701] [Citation(s) in RCA: 6] [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] [Indexed: 05/31/2023]
Abstract
We report on the strong temperature-dependent thermal expansion, α(D), in CdS quantum dots (QDs) embedded in a glass template. We have performed a systematic study by using the temperature-dependent first-order Raman spectra, in CdS bulk and in dot samples, in order to assess the size dependence of α(D), and where the role of the compressive strain provoked by the glass host matrix on the dot response is discussed. We report the Grüneisen mode parameters and the anharmonic coupling constants for small CdS dots with mean radius R ∼ 2.0 nm. We found that γ parameters change, with respect to the bulk CdS, in a range between 20 and 50%, while the anharmonicity contribution from two-phonon decay channel becomes the most important process to the temperature-shift properties.
Collapse
Affiliation(s)
- E S Freitas Neto
- Laboratório de Novos Materiais Isolantes e Semicondutores, Instituto de Física, Universidade Federal de Uberlândia, 38400-902 Uberlândia, Minas Gerais, Brazil.
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Villegas-Lelovsky L, Teodoro MD, Lopez-Richard V, Calseverino C, Malachias A, Marega E, Liang BL, Mazur YI, Marques GE, Trallero-Giner C, Salamo GJ. Anisotropic Confinement, Electronic Coupling and Strain Induced Effects Detected by Valence-Band Anisotropy in Self-Assembled Quantum Dots. Nanoscale Res Lett 2011; 6:56. [PMID: 27502678 PMCID: PMC3212094 DOI: 10.1007/s11671-010-9786-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 09/09/2010] [Indexed: 06/06/2023]
Abstract
A method to determine the effects of the geometry and lateral ordering on the electronic properties of an array of one-dimensional self-assembled quantum dots is discussed. A model that takes into account the valence-band anisotropic effective masses and strain effects must be used to describe the behavior of the photoluminescence emission, proposed as a clean tool for the characterization of dot anisotropy and/or inter-dot coupling. Under special growth conditions, such as substrate temperature and Arsenic background, 1D chains of In0.4Ga0.6 As quantum dots were grown by molecular beam epitaxy. Grazing-incidence X-ray diffraction measurements directly evidence the strong strain anisotropy due to the formation of quantum dot chains, probed by polarization-resolved low-temperature photoluminescence. The results are in fair good agreement with the proposed model.
Collapse
Affiliation(s)
- L Villegas-Lelovsky
- Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, 13565-905, Brazil.
- Instituto de Física, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, 38400-902, Brazil.
| | - M D Teodoro
- Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, 13565-905, Brazil
- Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - V Lopez-Richard
- Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, 13565-905, Brazil
| | - C Calseverino
- Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, 13565-905, Brazil
- Laboratório Nacional de Luz Síncrotron, Campinas, Brazil
| | - A Malachias
- Laboratório Nacional de Luz Síncrotron, Campinas, Brazil
| | - E Marega
- Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, 13560-970, Brazil
| | - B L Liang
- Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
- Department of Electrical Engineer, University of California, Los Angeles, CA, 90095, USA
| | - Yu I Mazur
- Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - G E Marques
- Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, 13565-905, Brazil
| | | | - G J Salamo
- Arkansas Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| |
Collapse
|
10
|
Villegas CEP, Tavares MRS, Marques GE. Anisotropy induced localization of pseudo-relativistic spin states in graphene double quantum wire structures. Nanotechnology 2010; 21:365401. [PMID: 20705968 DOI: 10.1088/0957-4484/21/36/365401] [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: 05/29/2023]
Abstract
We study the single-particle properties of Dirac Fermions confined to a double quantum wire system based on graphene. We map out the spatial regions where electrons in a given subband display the largest occupation probability induced by spatial anisotropic effects associated to the interaction strength between the graphene wires and the substrate. Here, the graphene-substrate interaction is considered as an ad hoc parameter which destroys the zero-gap observed in the relativistic Dirac cone characteristic of graphene electronic energy dispersions. Furthermore, the results indicate that the character of quasi-extended spin states, viewed by multisubband probability density function, is highly sensitive to spatial asymmetries and to the graphene-substrate interaction strength.
Collapse
Affiliation(s)
- Cesar E P Villegas
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil
| | | | | |
Collapse
|
11
|
Dantas NO, Serqueira EO, Carmo AP, Bell MJV, Anjos V, Marques GE. Energy transfer between CdS nanocrystals and neodymium ions embedded in vitreous substrates. Opt Lett 2010; 35:1329-1331. [PMID: 20436558 DOI: 10.1364/ol.35.001329] [Citation(s) in RCA: 5] [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: 05/29/2023]
Abstract
Experimental evidence has been observed for energy transfer from CdS nanocrystals, synthesized by the fusion method, to Nd(3+) ions embedded in vitreous substrates. These dot samples doped with neodymium have been investigated by combined optical absorption (OA), photoluminescence (PL), and time-resolved photoluminescence (PLRT) techniques. Radiative and nonradiative energy transfers between CdS dot and Nd(3+) ion levels, to our knowledge not reported before, can be clearly observed in the PL spectra where the emission band valleys correspond exactly to the energy absorption peaks of the doping ion. The PLRT data reinforce these energy transfer mechanisms in which the increasing overlap between the CdS PL band and the OA to the Nd(3+) levels decreases stimulated emissions from the doping ions.
Collapse
Affiliation(s)
- N O Dantas
- Laboratório de Novos Materiais Isolantes e Semicondutores-LNMIS, Instituto de Física, Universidade Federal de Uberlândia, 38400-902, Uberlândia, Minas Gerais, Brazil
| | | | | | | | | | | |
Collapse
|
12
|
Teodoro MD, Campo VL, Lopez-Richard V, Marega E, Marques GE, Gobato YG, Iikawa F, Brasil MJSP, Abuwaar ZY, Dorogan VG, Mazur YI, Benamara M, Salamo GJ. Aharonov-Bohm interference in neutral excitons: effects of built-in electric fields. Phys Rev Lett 2010; 104:086401. [PMID: 20366953 DOI: 10.1103/physrevlett.104.086401] [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: 08/24/2009] [Indexed: 05/29/2023]
Abstract
We report a comprehensive discussion of quantum interference effects due to the finite structure of neutral excitons in quantum rings and their first experimental corroboration observed in the optical recombinations. The signatures of built-in electric fields and temperature on quantum interference are demonstrated by theoretical models that describe the modulation of the interference pattern and confirmed by complementary experimental procedures.
Collapse
Affiliation(s)
- M D Teodoro
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, São Paulo, Brazil
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Lopez-Richard V, González JC, Matinaga FM, Trallero-Giner C, Ribeiro E, Sousa Dias MR, Villegas-Lelovsky L, Marques GE. Markovian and non-Markovian light-emission channels in strained quantum wires. Nano Lett 2009; 9:3129-3136. [PMID: 19663458 DOI: 10.1021/nl9012024] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have achieved conditions to obtain optical memory effects in semiconductor nanostructures. The system is based on strained InP quantum wires where the tuning of the heavy-light valence band splitting has allowed the existence of two independent optical channels with correlated and uncorrelated excitation and light-emission processes. The presence of an optical channel that preserves the excitation memory is unambiguously corroborated by photoluminescence measurements of free-standing quantum wires under different configurations of the incoming and outgoing light polarizations in various samples. High-resolution transmission electron microscopy and electron diffraction indicate the presence of strain effects in the optical response. By using this effect and under certain growth conditions, we have shown that the optical recombination is mediated by relaxation processes with different natures: one a Markov and another with a non-Markovian signature. Resonance intersubband light-heavy hole transitions assisted by optical phonons provide the desired mechanism for the correlated non-Markovian carrier relaxation process. A multiband calculation for strained InP quantum wires was developed to account for the description of the character of the valence band states and gives quantitative support for light hole-heavy hole transitions assisted by optical phonons.
Collapse
Affiliation(s)
- V Lopez-Richard
- Departamento de Fisica, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
|
15
|
Pereira MC, Marques GE, Studart N. Quantum-degeneracy effects in the mobility of the electron fluid on the surface of helium. Phys Rev B Condens Matter 1992; 46:1857-1859. [PMID: 10003841 DOI: 10.1103/physrevb.46.1857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
16
|
Cohen AM, Marques GE. Electronic structure of zinc-blende-structure semiconductor heterostructures. Phys Rev B Condens Matter 1990; 41:10608-10621. [PMID: 9993469 DOI: 10.1103/physrevb.41.10608] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
17
|
Marques GE, Studart N. Polaronic state of electrons on the surface of liquid-helium films: A self-consistent treatment. Phys Rev B Condens Matter 1989; 39:4133-4139. [PMID: 9948748 DOI: 10.1103/physrevb.39.4133] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
18
|
Chitta VA, Degani MH, Cohen AM, Marques GE. Dynamical mass effect on confined exciton states. Phys Rev B Condens Matter 1988; 38:8533-8536. [PMID: 9945628 DOI: 10.1103/physrevb.38.8533] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
19
|
Marques GE, Chitta VA, Degani MH, Hipólito O. Impurity-shifted polaron energy in semimagnetic Cd1-xMnxTe-CdTe quantum wells. Phys Rev B Condens Matter 1987; 36:5066-5069. [PMID: 9943536 DOI: 10.1103/physrevb.36.5066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|