## Topological Θ Theta Physics and Chern Structure Confirmed in Strontium Ruthenate Sr2RuO4 Nanofilms

by Tommy on 29/01/2017This is a long experimental treatise first reported by me here, beginning my axion adventure.

Topological Magneto Electric Effect by Chern Structure in Strontium Ruthenate – Sr_{2}RuO_{4}

You know me, I really don’t get interested in something unless it has contact with reality.

http://www.nature.com/articles/srep41291

Chern structure in the Bose-insulating phase of Sr_{2}RuO_{4} nanofilms, Hiroyoshi Nobukane, Toyoki Matsuyama and Satoshi Tanda, Scientific Reports 7, 41291 (23 January 2017), doi:10.1038/srep41291

The 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 Sr

_{2}RuO_{4}nanofilms by employing electric transport. We observed the superconductor-to-insulator transition by reducing the thickness of Sr_{2}RuO_{4}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 Θ = π/6 was determined by observing the topological magneto-electric effect in the Bose-insulating phase of Sr_{2}RuO_{4}nanofilms.

The *p*-wave nature of the superconductivity in Sr_{2}RuO_{4} is still fairly controversial.

**See also**: http://arxiv.org/abs/1408.3614

Emergence of the Chern structure using Sr_{2}RuO_{4} nanofilms, Hiroyoshi Nobukane, Toyoki Matsuyama and Satoshi Tanda (6 August 2015)

We discovered a fractional Chern structure in chiral superconducting Sr

_{2}RuO_{4}nanofilms by employing electric transport. By using Sr_{2}RuO_{4}single crystals with nanoscale thickness, a fractional Hall conductance was observed without an external magnetic field. The Sr_{2}RuO_{4}nanofilms enhanced the superconducting transition temperature to about 3 K. We found an anomalous induced voltage with temperature and thickness dependence, and the switching behavior of the induced voltage appeared 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 angleθ=π/6 is determined by observing the topological magneto-electric effect in Sr_{2}RuO_{4}nanofilms.

**See also also**: http://www.sciencedirect.com/science/article/pii/S0921452614008965

Topological electromagnetic response in the chiral superconductor Sr_{2}RuO_{4}, Hiroyoshi Nobukane, Toyoki Matsuyama and Satoshi Tanda, Physica B: Condensed Matter, 460, 168–170 (1 March 2015), doi:10.1016/j.physb.2014.11.062

We report the observation of a fractional topological magneto-electric effect in Sr

_{2}RuO_{4}single crystal thin films by measuring the electric transport properties. In the absence of an external magnetic field, the surface transport in Sr_{2}RuO_{4}thin films exhibited a fractional quantum Hall conductance in the superconducting state. The fractional magnetic-field-induced electric polarization was observed under zero bias current. We can understand the fractional quantum Hall conductance as a consequence of the observation of the (2+1) – dimensional topological surface state in the (3+1) – dimensional fractional topological magneto-electric effect in Sr_{2}RuO_{4}thin films.

When I was first learning about axion physics, I considered this to be the big breakthrough.

The Scientific Reports article is open. Enjoy!

Is my axion adventure over now?

You tell me. I wanna know.

lifeform@charter.net
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