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We report the temperature evolution of the Dirac band in semiconducting zirconium pentatelluride (ZrTe$_5$) using magneto-infrared spectroscopy. We find that the band gap is temperature independent at low temperatures and increases with…

We obtained numerical and closed-form analytic expressions for finite-temperature plasmon dispersion relations for intrinsic graphene in the presence of a finite energy gap in the energy spectrum. The calculations were carried out using the…

Mesoscale and Nanoscale Physics · Physics 2015-04-20 Andrii Iurov , Godfrey Gumbs , Danhong Huang , V. Silkin

We have studied the magnetic properties of (GaMnAs)m/(GaAs)n superlattices with magnetic GaMnAs layers of thickness between 8 and 16 molecular layers (ML) (23-45 \AA), and with nonmagnetic GaAs spacers from 4 ML to 10 ML (11-28 \AA). While…

Extensive Kerr microscopy studies reveal a strongly temperature dependent domain wall dynamics in Hall-bars made from compressively strained GaMnAs. Depending on the temperature magnetic charging of domain walls is observed and nucleation…

Materials Science · Physics 2015-05-14 J. Honolka , L. Herrera Diez , R. K. Kremer , K. Kern , E. Placidi , F. Arciprete

We study the controlled introduction of defects in GaMnAs by irradiating the samples with energetic ion beams, which modify the magnetic properties of the DMS. Our study focuses on the low-carrier-density regime, starting with as-grown…

Disordered Systems and Neural Networks · Physics 2010-06-14 E. H. C. P. Sinnecker , G. M. Penello , T. G. Rappoport , M. M. Sant'Anna , D. E. R. Souza , M. P. Pires , X. Liu , J. K. Furdyna

MnAs has been grown by means of MBE on the GaN(0001)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition…

Materials Science · Physics 2009-11-13 I. A. Kowalik , B. J. Kowalski , R. J. Iwanowski , K. Kopalko , E. Łusakowska , M. Sawicki

We study the effects of temperature on the band structure of the Bi$_2$Se$_3$ family of topological insulators using first-principles methods. Increasing temperature drives these materials towards the normal state, with similar…

Materials Science · Physics 2016-11-30 Bartomeu Monserrat , David Vanderbilt

The observations of the prompt emission of gamma ray bursts (GRB) by GLAST Burst Monitor (GBM), on board Fermi Gamma-ray Space Telescope, suggest the presence of a significant thermal spectral component, whose origin is not well understood.…

High Energy Astrophysical Phenomena · Physics 2017-03-29 Priya Bharali , Sunder Sahayanathan , Ranjeev Misra , Kalyanee Boruah

We present temperature-dependent infrared spectroscopic studies of CaMnSb2, a proposed threedimensional topological material. The low plasma edge in the reflectivity spectrum and small Drude component in the optical conductivity indicate a…

Knowing the electronic structure of a material is essential in energy applications to rationalize its performance and propose alternatives. Materials for thermoelectric applications are generally small-gap semiconductors and should have a…

Materials Science · Physics 2020-03-09 A. Berche , M. Talla Noutack , M. -L. Doublet , P. Jund

The effect of short-time and long-time annealing at 250C on the conductivity, hole density, and Curie temperature of GaMnAs single layers and GaMnAs/InGaMnAs heterostructures is studied by in-situ conductivity measurements as well as Raman…

Condensed Matter · Physics 2009-11-10 W. Limmer , A. Koeder , S. Frank , M. Glunk , W. Schoch , V. Avrutin , K. Zuern , R. Sauer , A. Waag

MnAs films grown on GaAs (001) exhibit a progressive transition between hexagonal (ferromagnetic) and orthorhombic (paramagnetic) phases at wide temperature range instead of abrupt transition during the first-order phase transition. The…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Magalhaes-Paniago , L. N. Coelho , B. R. A. Neves , H. Westfahl , F. Iikawa , L. Daweritz , C. Spezzani , M. Sacchi

Single-phase Ni0.46Mn0.54As films with strained C1b symmetry have been successfully grown on GaAs (001) substrates by molecular-beam epitaxy. The epitaxial relationship between the film and the substrate has been studied using synchrotron…

Materials Science · Physics 2019-01-30 J. L. Ma , H. L. Wang , X. M. Zhang , S. Yan , W. S. Yan , J. H. Zhao

Thermoelectric power, electrical conductivity, and high field Hall effect were studied over a broad temperature range in ferromagnetic Ga(1-x)Mn(x)As epitaxial layers (0.015<x<0.06). Thermoelectric power analysis gives the information about…

We calculate the Coulomb interaction induced density, temperature and magnetization dependent many-body band-gap renormalization in a typical diluted magnetic semiconductor GaMnAs in the optimally-doped metallic regime as a function of…

Materials Science · Physics 2007-05-23 Ying Zhang , S. Das Sarma

Gallium nanoparticles (Ga-NPs) exhibit promising plasmonic properties spanning ultraviolet to infrared spectral regions, making them suitable for diverse nanophotonic applications. However, the synthesis of uniform and ordered Ga-NP arrays…

We report the results of a detailed study of the structural, magnetic and magnetotransport properties of as-grown and annealed Ga0.91Mn0.09As thin films grown on (311)A and (311)B GaAs substrates. The high Curie temperature and hole density…

Materials Science · Physics 2009-11-11 K. Y. Wang , K. W. Edmonds , L. X. Zhao , M. Sawicki , R. P. Campion , B. L. Gallagher , C. T. Foxon

We study the effects of time-dependent substrate/film temperature in the deposition of a mesoscopically thick film using a statistical model that accounts for diffusion of adatoms without lateral neighbors whose coefficients depend on an…

Statistical Mechanics · Physics 2013-10-30 T. A. de Assis , F. D. A. A. Reis

The temperature renormalization of the bulk band structure of a topological crystalline insulator, SnTe, is calculated using first principles methods. We explicitly include the effect of thermal-expansion-induced modification of electronic…

Low temperature photoluminescence and photoluminescence excitation measurements have been performed in a set of InGaAs/GaAs samples with different indium molar fraction, well width, growth conditions and post-growth treatment. This has…

Condensed Matter · Physics 2009-10-28 A. Polimeni , A. Patanè , M. Grassi Alessi , M. Capizzi , F. Martelli , A. Bosacchi , S. Franchi