2024-03-28T15:17:25Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/646662022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116Chern structure in the Bose-insulating phase of Sr2RuO4 nanofilmsNobukane, HiroyoshiMatsuyama, ToyokiTanda, Satoshiopen accessCreative Commons Attribution 4.0 International400The quantum anomaly that breaks the symmetry, for example the parity and the chirality, in the quantization leads to a physical quantity with a topological Chern invariant. We report the observation of a Chern structure in the Bose-insulating phase of Sr2RuO4 nanofilms by employing electric transport. We observed the superconductor-to-insulator transition by reducing the thickness of Sr2RuO4 single crystals. The appearance of a gap structure in the insulating phase implies local superconductivity. Fractional quantized conductance was observed without an external magnetic field. We found an anomalous induced voltage with temperature and thickness dependence, and the induced voltage exhibited switching behavior when we applied a magnetic field. We suggest that there was fractional magnetic-field-induced electric polarization in the interlayer. These anomalous results are related to topological invariance. The fractional axion angle Theta = pi/6 was determined by observing the topological magneto-electric effect in the Bose-insulating phase of Sr2RuO4 nanofilms.Nature Publishing Group2017-01-23engjournal articleVoRhttp://hdl.handle.net/2115/64666https://doi.org/10.1038/srep412912045-2322Scientific reports741291https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/64666/1/srep41291.pdfapplication/pdf1.14 MB2017-01-23