Photoemission Studies of Strongly Correlated Materials including the Cobaltates and Ruthenates

Peter D. Johnson

(Brookhaven National Laboratory, USA)


Abstract: High Resolution Photoemission is used to examine the nature of the elementary excitations in strongly correlated materials.  Detailed photoemission studies of the scattering rates of these excitations allow us to identify the microscopic origin or several transport measurements.  In particular we demonstrate that a dimensional crossover observed in the transport properties correlates with the formation of well defined quasiparticles in the 2-D planes of these layered materials.  Studies of the scattering rates observed around the Fermi surface of the ruthenate, Sr2RuO4, point to the microscopic origin of the Fermi liquid behavior observed in this material at low temperatures.  Further in this system we demonstrate a distinct orbital dependence in the scattering rates.