Large Chern Number and Edge Currents in Sr2RuO4.
Large Chern Number and Edge Currents in Sr2RuO4.
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DOI：
10.1103/physrevlett.115.087003
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发表时间：
2014-10
影响因子：
8.6
通讯作者：
Thomas Scaffidi;S. Simon
中科院分区：
文献类型：
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作者：
Thomas Scaffidi;S. Simon
我们从弱耦合微观计算中发现，Sr_2RuO_4中最有利的手征超导序参量的Chern数为|C| =7。这个序参数的两个主要分量由sin（3 k（x））+isin（3 k（y））和sin（k（x））cos（k（y））+isin（k（y））cos（k（x））给出，并且位于与通常假设的间隙函数sin（k（x））+isin（k（y））相同的四点群的不可约表示E（u）中。后一种间隙函数导致C=1，前两种间隙函数导致C=-7，这对于E_{u}间隙函数也是允许的，因为四重对称性仅固定C模4。因为它表明，边缘电流的一个|C|>1的超导体在连续极限下完全消失，并且在晶格上可以很强地约化，这种形式的序参量可以帮助解决实验观察到的时间反演对称性破缺和在Sr_2RuO_4中没有观察到边缘电流之间的矛盾。
We show from a weak-coupling microscopic calculation that the most favored chiral superconducting order parameter in Sr2RuO4 has a Chern number of |C|=7. The two dominant components of this order parameter are given by sin(3k(x))+isin(3k(y)) and sin(k(x))cos(k(y))+isin(k(y))cos(k(x)) and lie in the same irreducible representation E(u) of the tetragonal point group as the usually assumed gap function, sin(k(x))+isin(k(y)). While the latter gap function leads to C=1, the two former lead 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.