Why is Sr2RuO4 not a high Tc superconductor? Electron correlation, Hund's coupling and p-wave instability
1996; Elsevier BV; Volume: 223-224; Linguagem: Inglês
10.1016/0921-4526(96)00155-x
ISSN1873-2135
Autores Tópico(s)Magnetic and transport properties of perovskites and related materials
ResumoSr2RuO4 is a layered superconductor with a Tc ≈ 0.95 K. The electrical resistivity is strongly anisotropic and has an unusual T dependence: ϱab ≈ T2 for T < K and ϱab ≈ T for T > 100 K; the ratio ϱc/ϱab is about 850 around 4 K and 220 around 290 K. dHvA and SdH experiments show the presence of three anisotropic ‘Fermi surfaces’. Experiments on Sr2RuO4 and related oxides indicate that this conductor is close to a spin 1 Mott insulating state. We present a model for the insulating and conducting states of these compounds and a mechanism for the metal-insulator transition. We argue that there are two bands of non-Fermi liquids which are close to half filling and an almost full band. The residual Hund's coupling in this (primarily 4d) band is argued to cause triplet correlations among the low-energy spinon excitations of the two bands of non-Fermi liquids below about 100 K. Based on this, we suggest that the experimentally observed superconducting state is likely to be a triplet p-wave type. Some other predictions are also made.
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