Low-Temperature Hall Effect in Substituted Sr2RuO4

TL;DR

This study investigates how substituting elements in Sr2RuO4 affects its Hall effect and magnetoresistance, revealing a sharp Hall coefficient change at low doping levels unrelated to Fermi surface or magnetic changes.

Contribution

It provides new insights into the doping-dependent Hall effect in Sr2RuO4, highlighting a sharp Hall coefficient change at low substitution levels without Fermi surface or magnetic instability.

Findings

Sharp jump and sign change in Hall coefficient at y ~ 0.01

Hall coefficient change is unrelated to Fermi surface topography

High purity allows measurement of strong-field Hall effect

Abstract

We report the results of a study of the Hall effect and magnetoresistance in single crystals of Sr2RuO4 in which Sr^(2+) has been substituted by La^(3+) (Sr(2-y)La(y)RuO(4)) or Ru^(4+) by Ti^(4+) (Sr(2)Ru(1-x)Ti(x)O(4)). For undoped Sr2RuO4, the purity is so high that the strong-field Hall coefficient can be measured for fields above 4 T. The conventional weak-field Hall coefficient as a function of doping shows a sharp jump and sign change at y ~ 0.01 that is unrelated to either a sharp change in Fermi-surface topography or a magnetic instability. The implications of these results are discussed.