Giant reversible nanoscale piezoresistance at room temperature in Sr2IrO4 thin films

Neus Domingo,* Laura López-Mir, Markos Paradinas, Vaclav Holy, Jakuv Železný, Di Yi, Siriyara J. Suresha, Jian Liu, Claudy Rayan Serrao, Ramamoorthy Ramesh, Carmen Ocal, Xavi Martí* and Gustau Catalan*.     
Nanoscale, 2015,7, 3453-3459

DOI: 10.1039/C4NR06954D 

Layered iridates have been the subject of intense scrutiny on account of their unusually strong spin–orbit coupling, which opens up a narrow bandgap in a material that would otherwise be a metal. This insulating state is very sensitive to external perturbations. Here, we show that vertical compression at the nanoscale, delivered using the tip of a standard scanning probe microscope, is capable of inducing a five orders of magnitude change in the room temperature resistivity of Sr₂IrO₄. The extreme sensitivity of the electronic structure to anisotropic deformations opens up a new angle of interest on this material, with the giant and fully reversible perpendicular piezoresistance rendering iridates as promising materials for room temperature piezotronic devices.