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ISO data taken with the long-wavelength imaging photo-polarimeter ISOPHOT are presented of 18 pre-stellar cores at three far-infrared wavelengths - 90, 170 and 200 microns. Most of the cores are detected clearly at 170 and 200 but only one…

Astrophysics · Physics 2009-11-07 D. Ward-Thompson , P. Andre , J. M. Kirk

We report the observation of transverse electric polarized electroluminescence from InAs/AlInAs quantum dash quantum cascade structures up to room temperature. The emission is attributed to the electric field confined along the shortest…

Optics · Physics 2015-06-11 V. Liverini , L. Nevou , F. Castellano , A. Bismuto , M. Beck , Fabian Gramm , J. Faist

We measured phonon dispersion in single crystal EuTiO$_3$ using inelastic x-ray scattering. A structural transition to an antiferrodistortive phase was found at a critical temperature $T_0$=287$\pm$1 K using powder and single-crystal x-ray…

Strongly Correlated Electrons · Physics 2015-06-11 David S. Ellis , Hiroshi Uchiyama , Satoshi Tsutsui , Kunihisa Sugimoto , Kenichi Kato , Daisuke Ishikawa , Alfred Q. R. Baron

The contribution to the low frequency internal friction and the thermal conductivity due to optically vibrating edge dislocation dipoles is calculated within the modified Granato-Lucke string model. The results are compared with the recent…

Disordered Systems and Neural Networks · Physics 2009-11-10 D. V. Churochkin , S. Sahling , V. A. Osipov

Dielectric spectroscopy covering more than 18 decades of frequency has been performed on propylene carbonate in its liquid and supercooled-liquid state. Using quasi-optic submillimeter and far-infrared spectroscopy the dielectric response…

Disordered Systems and Neural Networks · Physics 2009-10-31 U. Schneider , P. Lunkenheimer , R. Brand , A. Loidl

The infrared reflectivity of a $\rm La_{0.67}Ca_{0.33}MnO_3$ single crystal is studied over a broad range of temperatures (78-340 K), magnetic fields (0-16 T), and wavenumbers (20-9000 cm$^{-1}$). The optical conductivity gradually changes…

Strongly Correlated Electrons · Physics 2019-08-17 A. V. Boris , N. N. Kovaleva , A. V. Bazhenov , P. J. M. van Bentum , Th. Rasing , S-W. Cheong , A. V. Samoilov , N. -C. Yeh

The microwave, near-millimetre and infrared (IR) dielectric response of Srn+1TinO3n+1 (n=1-4) Ruddlesden-Popper homologous series was studied in the temperature range 10 to 300 K. Remarkable softening of the polar optical mode was observed…

Materials Science · Physics 2007-05-23 D. Noujni , S. Kamba , A. Pashkin , V. Bovtun , J. Petzelt , A-K. Axelsson , N. McN Alford , P. L. Wise , I. M. Reaney

We provide a detailed description of the quantum interferometric thermometer, which is a device that estimates the temperature of a sample from the measurements of the optical phase. For the first time, we rigorously analyze the operation…

Quantum Physics · Physics 2015-09-15 Marcin Jarzyna , Marcin Zwierz

The collective amplitude mode of the order parameter in displacive ferroelectrics, termed the ferron, represents the amplitude fluctuations of long-range ordered polarization. At temperatures well below phase transition temperature $T_c$,…

Materials Science · Physics 2025-07-30 G. D. Zhao , F. Yang , L. Q. Chen

The reflectance of graphene is investigated in the framework of the Dirac model with account of its realistic properties, such as nonzero chemical potential and band gap, at any temperature. For this purpose, the exact reflection…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 G. L. Klimchitskaya , V. M. Mostepanenko , V. M. Petrov

We develop a temperature dependent empirical pseudopotential theory to study the electronic and optical properties of self-assembled quantum dots (QDs) at finite temperature. The theory takes the effects of both lattice expansion and…

Materials Science · Physics 2015-06-04 Jianping Wang , Ming Gong , Guang-Can Guo , Lixin He

An infrared study of the phonon spectra of ZrW2O8 as a function of temperature which includes the low energy (2-10 meV) region relevant to negative thermal expansion is reported and discussed in the context of specific heat and neutron…

Materials Science · Physics 2010-07-28 Jason N. Hancock , Chandra Turpen , Zack Schlesinger , Glen Kowach , Art Ramirez

X-ray and neutron powder diffraction data as a function of temperature are analyzed for the colossal dielectric constant material CaCu3Ti4O12. The local structure is studied using atomic pair distribution function analysis. No evidence is…

Materials Science · Physics 2009-11-10 E. S. Bozin , V. Petkov , P. W. Barnes , P. M. Woodward , T. Vogt , S. D. Mahanti , S. J. L. Billinge

We have investigated crystal field and phonon dynamics of the multiferroic orthoferrite DyFeO$_3$ via polarized infrared spectroscopy. Reflectance of single crystals was measured in the far- to mid-infrared spectral range at range of…

Strongly Correlated Electrons · Physics 2013-02-14 A. D. LaForge , J. Whalen , T. Siegrist , A. P. Ramirez , Z. Schlesinger

We introduce a technique based on infrared thermal emission, termed depth thermography, that can remotely measure the temperature distribution beneath the surface of certain objects. Depth thermography utilizes the thermal-emission spectrum…

Optics · Physics 2019-08-22 Yuzhe Xiao , Chenghao Wan , Alireza Shahsafi , Jad Salman , Mikhail A. Kats

Polarized Raman, IR and time-domain THz spectroscopy of orthorhombic lead zirconate single crystals yielded a comprehensive picture of temperature-dependent quasiharmonic frequencies of its low-frequency phonon modes. It is argued that…

Materials Science · Physics 2014-05-21 J. Hlinka , T. Ostapchuk , E. Buixaderas , C. Kadlec , P. Kuzel , I. Gregora , J. Kroupa , M. Savinov , J. Drahokoupil , J. Dec

Hard X-ray and extremely low energy bulk-sensitive photoelectron spectroscopy has been performed in the temperature range of 100-330 K for Fe3O4. In the high temperature phase just above the Verwey transition, the intensity at the Fermi…

Solar observations from millimeter to ultraviolet wavelengths show that there is a temperature minimum between photosphere and chromosphere. Analysis based on semi-empirical models locate this point at about 500 km over the photosphere. The…

Solar and Stellar Astrophysics · Physics 2015-06-18 Victor De la Luz , Miguel Chavez , Emanuele Bertone , Guillermo Gimenez de Castro

We present results of first-principles calculations of the frequency-dependent polarizabilities of all alkali atoms for light in the wavelength range 300-1600 nm, with particular attention to wavelengths of common infrared lasers. We…

Atomic Physics · Physics 2009-11-11 M. S. Safronova , Bindiya Arora , Charles W. Clark

The nature of dielectric echoes in amorphous solids at low temperatures is investigated. It is shown that at long delay times the echo amplitude is determined by a small subset of two level systems (TLS) having negligible relaxation and…