Anisotropic electric conductivity of delafossite PdCoO2 studied by angle-resolved photoemission spectroscopy

Phys Rev Lett. 2009 Jun 26;102(25):256404. doi: 10.1103/PhysRevLett.102.256404. Epub 2009 Jun 24.


An explicit connection between the electronic structure and the anisotropic high conductivity of delafossite-type PdCoO2 has been established by angle-resolved photoemission spectroscopy (ARPES) and core-level x-ray photoemission spectroscopy. The ARPES spectra show that a large hexagonal electronlike Fermi surface (FS) consists of very dispersive Pd 4d states. The carrier velocity and lifetime are determined from the ARPES data, and the conductivity is calculated by a solution of the Boltzmann equation, which demonstrates that the high anisotropic conductivity originates from the high carrier velocity, the large two-dimensional FS, and the long lifetime of the carriers.