paper

Effective gauge field theory of the t-J model in the charge-spin separated state and its transport properties

arXiv:cond-mat/0103007 · doi:10.1103/PhysRevB.64.104516

Abstract

We study the slave-boson t-J model of cuprates with high superconducting transition temperatures, and derive its low-energy effective field theory for the charge-spin separated state in a self-consistent manner. The phase degrees of freedom of the mean field for hoppings of holons and spinons can be regarded as a U(1) gauge field, . The charge-spin separation occurs below certain temperature, , as a deconfinement phenomenon of the dynamics of . Below certain temperature , the spin-gap phase develops as the Higgs phase of the gauge-field dynamics, and acquires a mass . The effective field theory near takes the form of Ginzburg-Landau theory of a complex scalar field coupled with , where represents d-wave pairings of spinons. Three dimensionality of the system is crucial to realize a phase transition at . By using this field theory, we calculate the dc resistivity . At , is proportional to . At , it deviates downward from the -linear behavior as . When the system is near (but not) two dimensional, due to the compactness of the phase of the field , the exponent deviates from its mean-field value 1/2 and becomes a nonuniversal quantity which depends on temperature and doping. This significantly improves the comparison with the experimental data.

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