Particle-flux separation of electrons in the half-filled Landau level: Chargeon-fluxon approach

Abstract

We have previously studied the phase structure at finite temperatures of the Chern-Simons (CS) gauge theory coupled with fermions by using lattice gauge theory. In this paper, we formulate the “chargeon-fluxon” representation of electrons and use it to reinvestigate the phenomenon of particle-flux separation (PFS) of electrons in the half-filled Landau level. We start with a lattice system of fermions interacting with a CS gauge field, and introduce two slave operators named chargeon and fluxon that carry the CS charge and flux, respectively. The original fermion, the composite fermion of Jain, is a composite of a chargeon and a fluxon. We further rewrite the model by introducing an auxiliary link field, the phase of which behaves as a gauge field gluing chargeons and fluxons. Then we study a confinement-deconfinement transition of that gauge field by using the theory of separation phenomena as in the previous paper. The residual four-Fermi interactions play an important role to determine the critical temperature T PFS, below which the PFS takes place. The new representation has some advantages; (1) It allows a field-theoretical description also for the flux degrees of freedom. (2) It has a close resemblance to the slave-boson or slave-fermion representations of the t- J model of high- T c superconductors in which an electron is a composite of a holon and a spinon. This point opens a way to understand the two typical separation phenomena in strongly correlated electron systems in a general and common setting.