Performance of IR-VUV normal incidence monochromator beamline at UVSOR

Fukui, Kiichi; Miura, Hayato; Nakagawa, Hideyuki; Shimoyama, Iwao; Nakagawa, Kazumichi; Okamura, Hidekazu; Nanba, Tetsuya; Hasumoto, Masami; Kinoshita, Toyohiko

doi:10.1016/s0168-9002(01)00425-9

Cited by 32 publications

(22 citation statements)

References 4 publications

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“…The σ(ω) spectra were derived from the Kramers-Kronig analysis (KKA) of the R(ω) spectrum in the wide energy range up to 30 eV measured at the beam line 7B of UVSOR-II, Institute for Molecular Science, Okazaki, Japan. 18 Since R(ω) above 1.2 eV has no significant temperature dependence, the R(ω) above 1.2 eV at 300 K was extrapolated to the experimental R(ω) obtained at lower temperatures below 1.2 eV. In the energy ranges below 2 meV and above 30 eV, the spectra were extrapolated using the Hagen-Rubens function [R(ω) = 1−(2ω/πσ DC ) 1/2 ] and R(ω) ∝ ω −4 , respectively.…”

Section: Experimental and Band Calculation Methodsmentioning

confidence: 99%

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Kimura

Aoki

2007

J. Phys. Soc. Jpn.

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The temperature dependence of the optical conductivity spectrum of an itinerant ferromagnetic material, ZrZn2, was obtained and the dynamical effective mass and the scattering rate were derived. A renormalized Drude peak with a heavy effective mass developed at low temperatures. The effective mass rapidly increased below ω = 10 meV and at 10 K it was observed to be 3 times heavier than that at 300 K. The scattering rate also rapidly decreased below 10 meV at 10 K. These results indicate the creation of heavy quasiparticles at low temperatures due to spin fluctuations.

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Section: Experimental and Band Calculation Methodsmentioning

confidence: 99%

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Kimura

Aoki

2007

J. Phys. Soc. Jpn.

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“…At T = 300 K, R(ω) was measured for energies 1.2-30 eV by using synchrotron radiation. 15) In order to obtain σ(ω) via KKA of R(ω), the spectra were extrapolated below 2 meV with a Hagen-Rubens function, and above 30 eV with a freeelectron approximation R(ω) ∝ ω −4 . 16) Electrical resistivity measurements were performed by a conventional ac four-probe method at a frequency of 19 Hz.…”

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confidence: 99%

Anisotropic Electronic Structure of the Kondo Semiconductor CeFe₂Al₁₀Studied by Optical Conductivity

2011

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We report temperature-dependent polarized optical conductivity [σ(ω)] spectra of CeFe2Al10, which is a reference material for CeRu2Al10 and CeOs2Al10 with an anomalous magnetic transition at 28 K. The σ(ω) spectrum along the b-axis differs greatly from that in the ac-plane, indicating that this material has an anisotropic electronic structure. At low temperatures, in all axes, a shoulder structure due to the optical transition across the hybridization gap between the conduction band and the localized 4f states, namely c-f hybridization, appears at 55 meV. However, the gap opening temperature and the temperature of appearance of the quasiparticle Drude weight are strongly anisotropic indicating the anisotropic Kondo temperature. The strong anisotropic nature in both electronic structure and Kondo temperature is considered to be relevant the anomalous magnetic phase transition in CeRu2Al10 and CeOs2Al10.

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“…At T = 300 K, R(ω) was measured for energies 1.2-30 eV by using synchrotron radiation. [18] In order to obtain σ(ω) via a KKA of R(ω) the spectra were extrapolated below 2 meV with R(ω) = 1 − (2ω/πσ DC ) 1/2 and above 30 eV with a freeelectron approximation R(ω) ∝ ω −4 . [7] The temperature dependence of the R(ω) spectra of YbRh 2 Si 2 is shown in Fig.…”

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Optical observation of non-Fermi-liquid behavior in the heavy fermion state ofYbRh2Si2

et al. 2006

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We report far-infrared optical properties of YbRh2Si2 for photon energies down to 2 meV and temperatures 0.4 -300 K. In the coherent heavy quasiparticle state, a linear dependence of the lowenergy scattering rate on both temperature and photon energy was found. We relate this distinct dynamical behavior different from that of Fermi liquid materials to the non-Fermi liquid nature of YbRh2Si2 which is due to its close vicinity to an antiferromagnetic quantum critical point.PACS numbers: 71.10. Hf, 71.27.+a, The investigation of 4f -containing metals by farinfrared optical spectroscopy provides valuable insight into the nature of strong electronic correlations. This in particular holds true for heavy fermion (HF) compounds where at low temperatures a weak 4f -conduction electron (cf -)hybridization generates mass-renormalized quasiparticles with a coherent ground state which is in many HF systems of the Landau Fermi liquid (LFL) type.[1] The quasiparticles influence thermodynamic quantities which are described in terms of a large effective mass m * exceeding the free electron mass m 0 by three orders of magnitude. Furthermore, in typical HF materials, below a single-ion Kondo temperature (T K ), the coherent state is characterized by a dynamical screening of the 4f magnetic moments through the conduction electrons. Several highly correlated metals exhibit so-called nonFermi liquid (NFL), i.e., strong deviations from a renormalized LFL behavior when T → 0 K. [1] The system YbRh 2 Si 2 studied in this paper is one of a few clean stoichiometric HF metals with pronounced NFL behavior at ambient pressure which is related to both antiferromagnetic (AF) as well as ferromagnetic quantum critical spin fluctuations in close proximity to an AF quantum critical point (QCP). [2, 3, 4] Those NFL effects manifest as a divergence of the 4f -derived increment to the specific heat ∆C/T ∝ − ln T and in the electrical resistivity ρ(T ) showing a power law exponent close to 1 in a temperature range substantially larger than one decade and extending up to T ≃ 10 K.[5] Transport and thermodynamic properties are consistent with a single-ion Kondo temperature T K = 25 K (associated with the crystallineelectric-field-derived doublet ground state [6]).The electrodynamical response of HF systems is characterized by an optical conductivity σ(ω) which follows at room temperature the classical Drude model [σ(ω) = N e 2 τ /m * (1 + ω 2 τ 2 ); N : charge carrier density] with frequency independent m * and scattering rate 1/τ . [7] At low temperatures, upon entering the coherent state, large deviations are observed which are caused by many-body effects. Then a narrow, renormalized peak at zero photon energy ω = 0 eV is formed and a socalled hybridization gap appears which is related to the transition between the bonding and antibonding states resulting from the cf -hybridization. [8, 9, 10] The coherent part of the underlying strong electron-electron correlations are treated in an extended Drude model by renormalized and frequency dependent m * (ω)...

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Performance of IR-VUV normal incidence monochromator beamline at UVSOR

Cited by 32 publications

References 4 publications

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Anisotropic Electronic Structure of the Kondo Semiconductor CeFe₂Al₁₀Studied by Optical Conductivity

Optical observation of non-Fermi-liquid behavior in the heavy fermion state ofYbRh2Si2

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Performance of IR-VUV normal incidence monochromator beamline at UVSOR

Cited by 32 publications

References 4 publications

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn2

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn2

Anisotropic Electronic Structure of the Kondo Semiconductor CeFe2Al10Studied by Optical Conductivity

Optical observation of non-Fermi-liquid behavior in the heavy fermion state ofYbRh2Si2

Contact Info

Product

Resources

About

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Low-Energy Electrodynamics of Heavy Quasiparticles in ZrZn₂

Anisotropic Electronic Structure of the Kondo Semiconductor CeFe₂Al₁₀Studied by Optical Conductivity