Gap nodes and time reversal symmetry breaking in strontium ruthenate
Gap nodes and time reversal symmetry breaking in strontium ruthenate
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钌酸锶中的能隙节点和时间反演对称性破缺
DOI：
10.1140/epjb/e2003-00348-3
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
K. Wysokiński
中科院分区：
文献类型：
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作者：
J. F. Annett;B. L. Gyorffy;G. Litak;K. Wysokiński
摘要。我们研究了Sr2RuO4的超导态，基于现象学但轨道特定的电子-电子吸引描述和正常状态下电子结构的现实定量描述。我们发现一个具有“面内”和“面外”耦合强度分别为$U_{\parallel} = 40$ meV和$U_{\perp} = 48$ meV的简单模型可以定量详细地再现实验观察到的低温比热Cv(T)，超流体密度ns(T)和导热系数的幂律行为。此外，还预测了$\gamma$ -薄片上的准粒子谱是完全间隙的，相应的序参量打破了时间反转对称性。我们还研究了该模型在包含进一步相互作用常数时的稳定性，特别是轨道之间的“接近耦合”，这有助于费米表面的$\gamma$层和$\alpha$和$\beta$层。我们发现，在这种变化下，模型的预测是稳健的。最后，我们在模型中加入了对弱无序的描述，并探讨了它的一些后果。例如，我们证明了无序对有序参数的f波分量的影响比对p波分量的影响更显著。
Abstract.We study the superconducting state of Sr2RuO4 on the bases of a phenomenological but orbital specific description of the electron-electron attraction and a realistic quantitative account of the electronic structure in the normal state. We found that a simple model which features both ‘in plane’ and ‘out of plane’ coupling with strengths $U_{\parallel} = 40$ meV and $U_{\perp} = 48$ meV respectively reproduced the experimentally observed power law behaviour of the low temperature specific heat Cv(T), superfluid density ns(T) and thermal conductivity in quantitative detail. Moreover, it predicts that the quasi-particle spectrum on the $\gamma$-sheet is fully gaped and the corresponding order parameter breaks the time reversal symmetry. We have also investigated the stability of this model to inclusion of further interaction constants in particular ‘proximity coupling’ between orbitals contributing to the $\gamma$ sheet of the Fermi surface and the $\alpha$ and $\beta$ sheets. We found that the predictions of the model are robust under such changes. Finally, we have incorporated a description of weak disorder into the model and explored some of its consequences. For example we demonstrated that the disorder has a more significant effect on the f-wave component of the order parameter than on the p-wave one.