Séminaire du lundi 6 juin 2011 à 10h30

 Novel electronic states investigated by arpes: COBALTATES AND MONOSILICIDES

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris
Salle de Conférence (401)
4ème étage
Tour 23
Couloir  22-23

Alessandro Nicolaou (Synchrotron SOLEIL – Saint Aubin)


Résumé:
In cobaltates, metallic CoO2 planes can be doped from the Mott-insulator limit to the band insulator one. Surprisingly, signatures of strong correlations appear in proximity of the band insulator limit, where good metallicity coexists with Curie-Weiss susceptibility and high thermoelectric power. We evidenced the signatures of strong correlations in angle resolved photoemission (ARPES) spectra of cobaltates and quantified the strength of correlations when approaching the band- insulator limit. In the second part of my talk, I show very first Fermi surface mappings of MnSi compound. MnSi is considered to be a prototype of weakly itinerant ferromagnet and, in an unexpected way, presents a quantum critical point under pressure and non-Fermi liquid phases that extend well above the critical pressure pc. Nowadays, a determination of its electronic structure by ARPES is still lacking, due to difficulties in measuring single crystals compounds. I show how growing MnSi on Si(111) allows to perform high-resolution ARPES measurements.

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