Fermi surface properties in Sr₂RuO₄

We measured the de Haas-van Alphen (dHvA) effect, magnetoresistance and specific heat to clarify the two-dimensional Fermi surface properties of Sr₂RuO₄. From the angular dependence of the dHvA amplitude, we determined the Yamaji angle for three quasi-cylindrical Fermi surfaces α, β and γ to be 30.6° for the Fermi surface α, about 30° for β and 15.3° for γ. The cyclotron masses of sum and difference oscillatory components, m^*_{β ± α} and m^*_{γ ± α}, are found to be highly different from m^*_β + m^*_α and m^*_γ + m^*_α, respectively, for any field direction. The dHvA oscillation due to sums and differences is not due to the magnetic interaction but to the chemical potential oscillation for quasi-two-dimensional Fermi surfaces. The specific heat data are discussed from a viewpoint of a characteristic energy gap in a possible p-wave superconductor Sr₂RuO₄.