Origin of Hall-coefficient sign crossovers

Determine the microscopic origin of the strain-dependent Hall-coefficient sign crossovers in SrCrO3 thin films, including whether they result from a structural transition with Fermi-surface reconstruction associated with strain-induced Jahn–Teller distortions and orbital order.

Background

SrCrO3 thin films exhibit resistivity upturns at temperatures that correlate with epitaxial strain. These upturns occur near a crossover in the Hall coefficient, where the dominant charge carriers change from electron-like at high temperature to hole-like at low temperature.

The paper proposes that a strain-associated structural transition and Fermi-surface reconstruction could explain the crossover, potentially through reorganization of the electronic bands caused by Jahn–Teller distortions and orbital order. The authors explicitly state that this interpretation is not conclusive and that further investigation is required.fi

References

While the origin of these Hall sign crossovers remains to be established, a possible explanation could be a structural transition associated with a Fermi surface reconstruction. This scenario is compatible with the formation of orbital order, made possible by the reorganization of the electronic band structures induced by the strain-dependent JT distortion, as explored in , thereby changing the balance of electron and hole pockets in the Fermi surface. However, this is not yet conclusive, and further investigations are needed.

— Strain-Induced Metal-to-Insulator Transition in Antiferromagnetic SrCrO$_3$ Thin Films  (2609.20486 - Jöhr et al., 17 Sep 2026) in Section Results, subsection Transport