摘要 :
We have investigated the low-energy electronic structure of the heavy-fermion superconductor CeCoIn_5 by angle-resolved photoemission and band-structure calculations. We measured the Fermi surface and energy distribution maps alon...
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We have investigated the low-energy electronic structure of the heavy-fermion superconductor CeCoIn_5 by angle-resolved photoemission and band-structure calculations. We measured the Fermi surface and energy distribution maps along the high-Symmetry directions at hv= 100 eV and T=25 K. The compound has quasi-two-dimensional Fermi-surface sheets centered at the M-A line of the Brillouin zone. The band-structure calculations have been carried out within the local-density approximation where the 4f electrons have been treated either localized or itinerant. We discuss the comparison to the experimental data and the implications for the nature of the 4f electrons at the given temperature.
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摘要 :
We have investigated the low-energy electronic structure of the heavy fermion superconductor CeCoIn_5 by angle-resolved photoemission. We focus on the dispersion and the peak width of the prominent quasi-two-dimensional Fermi surf...
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We have investigated the low-energy electronic structure of the heavy fermion superconductor CeCoIn_5 by angle-resolved photoemission. We focus on the dispersion and the peak width of the prominent quasi-two-dimensional Fermi surface sheet at the corner o
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摘要 :
The 18.5 K superconductor PuCoGa_5 has many unusual properties, including those due to damage induced by self-irradiation. The superconducting transition temperature decreases sharply with time, suggesting a radiation-induced Fren...
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The 18.5 K superconductor PuCoGa_5 has many unusual properties, including those due to damage induced by self-irradiation. The superconducting transition temperature decreases sharply with time, suggesting a radiation-induced Frenkel defect concentration much larger than predicted by current radiation damage theories. Extended x-ray absorption fine-structure measurements demonstrate that while the local crystal structure in fresh material is well ordered, aged material is disordered much more strongly than expected from simple defects, consistent with strong disorder throughout the damage cascade region. These data highlight the potential impact of local lattice distortions relative to defects on the properties of irradiated materials and underscore the need for more atomic-resolution structural comparisons between radiation damage experiments and theory.
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An analysis of the optical properties of heavy fermion compounds is reported. We focus on the 1-1-5 series, where strong deviations of the spectra are seen from the predictions of the periodic Anderson model. Specifically we demon...
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An analysis of the optical properties of heavy fermion compounds is reported. We focus on the 1-1-5 series, where strong deviations of the spectra are seen from the predictions of the periodic Anderson model. Specifically we demonstrate that the differences between the experimental results and the theoretical predictions can be explained by accounting for the momentum dependence of the hybridization between the local moments and the conducting carriers. Furthermore we find correlations between the hybridization strength on a particular band and some properties of the 1-1-5 compounds. These correlations suggest that the momentum dependence of the hybridization has to be taken into account, for an understanding of the electronic properties of these heavy fermion compounds.
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The physical properties including magnetic susceptibility, magnetization, specific heat, and dynamic susceptibility x"(E) are reported for single crystals of the cubic UM_2Zn_(20) (M=Co,Rh) materials. Maxima in the thermodynamic d...
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The physical properties including magnetic susceptibility, magnetization, specific heat, and dynamic susceptibility x"(E) are reported for single crystals of the cubic UM_2Zn_(20) (M=Co,Rh) materials. Maxima in the thermodynamic data at T_(max) ～ 10 K for both compounds and a broad peak in x" (E) at 5 K in UCo_2Zn_(20) of width Γ=5 meV indicate a heavy-fermion state characterized by a Kondo temperature T_K K ～ 20-30 K arising from weak hybridization of f- and conduction-electron states. Anderson impurity model fits to the data in the Kondo limit including crystalline electric-field effects corroborate an ionic-like uranium electronic configuration in UM_2Zn_(20).
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摘要 :
Superconductivity develops from an attractive interaction between itinerant electrons that creates electron pairs, which condense into a macroscopic quantum state-the superconducting state. On the other hand, magnetic order in a m...
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Superconductivity develops from an attractive interaction between itinerant electrons that creates electron pairs, which condense into a macroscopic quantum state-the superconducting state. On the other hand, magnetic order in a metal arises from electron
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摘要 :
We report electron spin resonance experiments of Gd~(3+) in the Gd_mM_nIn_(3m+2n) (M=Rh,Ir; n=0,l; m=1,2) intermetallic compounds. For T>T_N～45 K, all compounds present a single Dysonian resonance and show a Korringa-like tempera...
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We report electron spin resonance experiments of Gd~(3+) in the Gd_mM_nIn_(3m+2n) (M=Rh,Ir; n=0,l; m=1,2) intermetallic compounds. For T>T_N～45 K, all compounds present a single Dysonian resonance and show a Korringa-like temperature dependence of the lin
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