Superfluid density in the slave-boson theory

作者：Zhong, Yin^*; Lu, Han-Tao; Luo, Hong-Gang

来源：European Physical Journal B, 2016, 89(2): 28.

DOI：10.1140/epjb/e2015-60280-5

• HIGH-TEMPERATURE SUPERCONDUCTORS
• PENETRATION DEPTH
• NORMAL-STATE
• DEPENDENCE
• PSEUDOGAP
• PHYSICS

Despite of the success of the slave-boson theory in capturing qualitative physics of high-temperature superconductors like cuprates, it fails to reproduce the correct temperature-dependent behavior of superfluid density, let alone the independence of the linear temperature term on doping in the underdoped regimes of hole-doped cuprate, a common experimental observation in different cuprates. It remains puzzling up to now in spite of intensive theoretical efforts. For electron-doped case, even qualitative treatment is not reported at present time. Here we revisit these problems and provide an alternative superfluid density formulation by using the London relation instead of employing the paramagnetic current-current correlation function. The obtained formula, on the one hand, provides the correct temperature-dependent behavior of the superfluid density in the whole temperature regime, on the other hand, makes the doping dependence of the linear temperature term substantially weaken and a possible interpretation for its independence on doping is proposed. As an application, electron-doped cuprate is studied, whose result qualitatively agrees with existing experiments and successfully explains the origin of d- to anisotropic s-wave transition across the optimal doping. Our result remedies some failures of the slave-boson theory as employed to calculate superfluid density in cuprates and may be useful in the understanding of the related physics in other strongly correlated systems, e.g. NaxCoO2 center dot yH(2)O and certain iron-based superconductors with dominating local magnetic exchange interaction.

• 出版日期2016-2-1
• 单位北京计算科学研究中心; 兰州大学