Giant reversible nanoscale piezoresistance at room temperature in Sr2IrO4 thin films

Layered iridates have been the subject of intense scrutiny on account of their unusually strong spin-orbit coupling, which opens up a narrow gap 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, and the giant and fully reversible perpendicular piezoresistance makes iridates a promising material for room temperature piezotronic devices

Giant reversible nanoscale piezoresistance at room temperature in Sr2IrO4 thin films

This article has been highlighted as "Hot Paper" in Nanoscale.-- Domingo, Neus et al.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.N.D wants to acknowledge the Spanish Ministerio de Ciencia e Innovación for a Ramon y Cajal research grant RYC-2010-06365. X.M. acknowledges the Grant Agency of the Czech Republic No. P204/11/P339. G.C. acknowledges ERC Starting Grant 308023. T.J. acknowledges ERC Advanced Grant 268066 and Praemium Academiae of the Academy of Sciences of the Czech Republic. Di Yi was sponsored by the National Science Foundation through the Penn State MRSEC. J.L. is supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 through the Quantum Material program in the Materials Sciences Division of Lawrence Berkeley National Laboratory. Financial support has been obtained under projects from the Spanish Ministerio de Economía y Competitividad under projects MAT2010-17771, MAT2010-20020, MAT2013-47869-C4-1-P, FIS2013-48668-C2-1-P and NANOSELECT CSD2007-00041 and Severo Ochoa Excellence Programme 2013-0295, and the Generalitat de Catalunya under projects 2014 SGR 733 and 2014 SGR 1216.Peer reviewe