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he frequency dependence in the mid IR from 900 to 1100 cm$^{-1}$ and far IR at 84 cm$^{-1}$ and temperature dependence from 35 to 330 K of the normal state Hall transport is reported in single crystal, optimally doped…

Superconductivity · Physics 2007-05-23 D. C. Schmadel , G. S. Jenkins , J. J. Tu , G. D. Gu , Hiroshi Kontani , H. D. Drew

Optical measurements and band structure calculations are reported on 3D Dirac materials. The electronic properties associated with the Dirac cone are identified in the reflectivity spectra of Cd$_3$As$_2$ and Na$_3$Bi single crystals. In…

With infrared ellipsometry we studied the response of the confined electrons in a $\gamma$-Al$_2$O$_3$/SrTiO$_3$ heterostructures in which they originate predominantly from oxygen vacancies. From the analysis of a so-called Berreman mode,…

The interplane optical spectrum of the organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br was investigated in the frequency range from 40 to 40,000 cm-1. The optical conductivity was obtained by Kramers-Kronig analysis of the reflectance.…

Superconductivity · Physics 2009-11-07 J. J. McGuire , T. Room , A. Pronin , T. Timusk , J. A. Schlueter , M. E. Kelly , A. M. Kini

We show that the infrared reflectance of the quasi-one dimensional charge-density-wave (CDW) conductor K0.3MoO3 (blue bronze) varies with position when a voltage greater than the CDW depinning threshold is applied. The spatial dependence…

Condensed Matter · Physics 2009-11-10 R. C. Rai , V. A. Bondarenko , J. W. Brill

We report the emergence of superconductivity in Ca2InN consisting of a 2-dimensional (2D) array of zigzag indium chains embedded between Ca2N layers. A sudden drop of resistivity and a specific-heat (Cp) jump attributed to the…

Superconductivity · Physics 2014-03-10 Sehoon Jeong , Satoru Matsuishi , Kimoon Lee , Yoshitake Toda , Sung Wng Kim , Hideo Hosono

We present a study of the lattice dynamical properties of superconducting SrPt$_3$P ($T_c = 8.4$ K) via high-resolution inelastic x-ray scattering (IXS) and ab initio calculations. Density functional perturbation theory including spin-orbit…

Superconductivity · Physics 2016-01-20 D. A. Zocco , S. Krannich , R. Heid , K. -P. Bohnen , T. Wolf , T. Forrest , A. Bossak , F. Weber

Lead chalcogenides are the promising thermoelectric (TE) materials having narrow band gap. The present work investigates the TE behaviour of PbSe in the temperature range 300-500 K. The transport properties of the sample have been studied…

One of the central tenets of conventional theories of superconductivity, including most models proposed for the recently discovered iron-pnictide superconductors, is the notion that only electronic excitations with energies comparable to…

Superconductivity · Physics 2011-03-07 A. Charnukha , P. Popovich , Y. Matiks , D. L. Sun , C. T. Lin , A. N. Yaresko , B. Keimer , A. V. Boris

We present the optical reflectance and conductivity spectra for non-oxide antiperovskite superconductor $MgCNi_{3}$ at different temperatures. The reflectance drops gradually over a large energy scale up to 33,000 cm$^{-1}$, with the…

Superconductivity · Physics 2009-11-11 P. Zheng , J. L. Luo , G. T. Liu , Y. L. Zhang , R. C. Yu , C. Q. Jin , N. L. Wang , M. Q. Tan

We analyze a random resistor-inductor-capacitor $(RLC)$ lattice model of 2-dimensional metal-insulator composites. The results are compared with Bruggeman's and Landauer's Effective Medium Approximations where a discrepancy was observed for…

Disordered Systems and Neural Networks · Physics 2009-11-10 Lotfi Zekri

We study electrical and optical conductivities of hole gas in $p$-doped bulk III-V semiconductors described by the Luttinger Hamiltonian. We provide exact analytical expressions of the Drude conductivity, inverse relaxation time for various…

Mesoscale and Nanoscale Physics · Physics 2016-09-29 Alestin Mawrie , Pushpajit Halder , Barun Ghosh , Tarun Kanti Ghosh

We have performed ellipsometric measurements of the far-infrared c-axis dielectric response of underdoped YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ single crystals. Here we report a detailed analysis of the temperature-dependent renormalization of…

Superconductivity · Physics 2016-08-15 C. Bernhard , D. Munzar , A. Golnik , C. T. Lin , A. Wittlin , J. Humlíček , M. Cardona

Electrons moving in graphene behave as massless Dirac fermions, and they exhibit fascinating low-frequency electrical transport phenomena. Their dynamic response, however, is little known at frequencies above one terahertz (THz). Such…

The ab-plane reflectivity of (Y{1-x}Prx)Ba2Cu3O7 thin films was measured in the 30-30000 cm-1 range for samples with x = 0 (Tc = 90 K), x = 0.4 (Tc = 35 K) and x = 0.5 (Tc = 19 K) as a function of temperature in the normal state. The…

Superconductivity · Physics 2009-11-07 R. P. S. M. Lobo , E. Ya. Sherman , D. Racah , Y. Dagan , N. Bontemps

Recently, there is a series of reports by Wang et al. on the superconductivity in K-doped p-terphenyl (KxC18H14) with the transition temperatures range from 7 to 123 Kelvin. Identifying the structural and bonding character is the key to…

Superconductivity · Physics 2018-05-24 Guo-Hua Zhong , Xiao-Hui Wang , Ren-Shu Wang , Jia-Xing Han , Chao Zhang , Xiao-Jia Chen , Hai-Qing Lin

We present experimental results on the optical absorption spectra of epitaxial graphene from the visible to the terahertz (THz) frequency range. In the THz range, the absorption is dominated by intraband processes with a frequency…

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

We report optical (6 meV - 4 eV) properties of a boride superconductor ZrB$_{12}$ ($T_c$ = 6 K) in the normal state from 20 to 300 K measured on high-quality single crystals by a combination of reflectivity and ellipsometry. The Drude…

We employ ultra-broadband terahertz-midinfrared probe pulses to characterize the optical response of photoinduced charge-carrier plasmas in high-resistivity silicon in a reflection geometry, over a wide range of excitation densities…

Materials Science · Physics 2015-02-11 Fanqi Meng , Mark D. Thomson , Bo E. Sernelius , Michael Jörger , Hartmut G. Roskos