Depletion of the density of states at the Fermi level in metallic colossal magnetoresistive manganites

Article

关键词: INSULATOR-TRANSITION;    DOPED MANGANITES;    TUNNELING SPECTROSCOPY;    ELECTRONIC-STRUCTURE;    LA1-XSRXMNO3;    LA0.8CA0.2MNO3;    PSEUDOGAP;    SPECTRA;   

DOI  :  10.1103/PhysRevB.68.134428

来源: SCIE

【 摘 要 】

We have performed tunneling spectroscopy measurements down to 4.2 K on single crystals of La0.75Sr0.25MnO3 and La0.7Ca0.3MnO3, which show the colossal magnetoresistive behavior in the ferromagnetic metallic phase. The tunneling spectroscopy measurements give information on the density of states (DOS) at and close to the Fermi level E-F. The observed energy dependence of the DOS is similar to that seen in correlated oxides with disorder, which is an important observation since it raises fundamental questions regarding the nature of the metallic state in these oxides. Measurements at low temperatures reveal that the DOS in these compounds show a depletion close to E-F, \E-E-F\less than or equal to15 meV; unlike that in conventional metals. The normalized DOS, close to E-F shows an energy dependence proportional to\E-E-F\(2) at low temperatures but remains finite as E-->E-F. The depth of the depletion is more in La0.7Ca0.3MnO3 compared to La0.75Sr0.25MnO3.

【 授权许可】

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