Hall effect of Sr3Ru2O7

The presence of Ru–O bilayers in the layered perovskite metal Sr3Ru2O7 could be intuitively expected to result in a doubling of the electronic structure of Sr2RuO4, i.e. four electron-like and two hole-like Fermi surface sheets. To check this, we have studied the weak-field Hall effect of Sr3Ru2O7 between 30 mK and 300 K. In contrast to the Hall coefficient in Sr2RuO4, which has two temperature dependent sign changes and is negative at low temperatures, that of Sr3Ru2O7 is positive over the whole range studied. Possible implications for its electronic structure are discussed.