Browsing by Author "Fang, C. P."

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Evolution of the pseudogap in Sr(1-x)Y(x)Al(2)Si(2) (x=0, 0.05, 0.1, and 0.15) probed via (27)Al nuclear magnetic resonance
(2011-03-28)
Fang, C. P.
;
Lue, C. S.
;
Young, Ben-Li
;
電子物理學系
;
Department of Electrophysics
With the aim of providing microscopic information about the electronic characteristics of SrAl(2)Si(2) and effects of chemical substitution on its pseudogap features, we carried out a study on Sr(1-x)Y(x)Al(2)Si(2) (x = 0, 0.05, 0.1, and 0.15) by means of (27)Al nuclear magnetic resonance (NMR) spectroscopy. For stoichiometric SrAl(2)Si(2), the temperature-dependent NMR Knight shift and spin-lattice relaxation rate are associated with a sharp feature in the electronic density of state within a pseudogap at around the Fermi level. On the other hand, the NMR observations for Y-substituted compounds exhibit ordinary metallic behavior, suggesting that the Fermi level has moved out of the pseudogap for these materials, resulting in the dominant Korringa process responsible for the observed relaxation rates.
Evolution of the pseudogap in Sr1-xYxAl2Si2 (x=0, 0.05, 0.1, and 0.15) probed via Al-27 nuclear magnetic resonance
(2011-03-28)
Fang, C. P.
;
Lue, C. S.
;
Young, Ben-Li
;
電子物理學系
;
Department of Electrophysics
With the aim of providing microscopic information about the electronic characteristics of SrAl2Si2 and effects of chemical substitution on its pseudogap features, we carried out a study on Sr1-xYxAl2Si2 (x = 0, 0.05, 0.1, and 0.15) by means of Al-27 nuclear magnetic resonance (NMR) spectroscopy. For stoichiometric SrAl2Si2, the temperature-dependent NMR Knight shift and spin-lattice relaxation rate are associated with a sharp feature in the electronic density of state within a pseudogap at around the Fermi level. On the other hand, the NMR observations for Y-substituted compounds exhibit ordinary metallic behavior, suggesting that the Fermi level has moved out of the pseudogap for these materials, resulting in the dominant Korringa process responsible for the observed relaxation rates.