Large Chern Number and Edge Currents in Sr2RuO4
Using the results of a previously reported microscopic calculation, we show that the most favored chiral superconducting order parameter in Sr2RuO4 has Chern number |C|=7 in the weak coupling limit. This order parameter has a momentum dependence of the type sin(k_x) cos(k_y) + i sin(k_y) cos(k_x) an...
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| Format: | Journal article |
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2014
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| Summary: | Using the results of a previously reported microscopic calculation, we show that the most favored chiral superconducting order parameter in Sr2RuO4 has Chern number |C|=7 in the weak coupling limit. This order parameter has a momentum dependence of the type sin(k_x) cos(k_y) + i sin(k_y) cos(k_x) and lies in the same irreducible representation E_u of the tetragonal point group as the usually assumed gap function sin(k_x) + i sin(k_y). While the latter gap function leads to C=1, the former leads to C =-7, which is also allowed for an E_u gap function since the tetragonal symmetry only fixes C modulo 4. Since it was shown that the edge currents of a |C|>1 superconductor vanish exactly in the continuum limit, and can be strongly reduced on the lattice, this form of order parameter could help resolve the conflict between experimental observation of time-reversal symmetry breaking and yet the absence of observed edge currents in Sr2RuO4. |
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