PARTICLE-FLUX SEPARATION OF ELECTRONS IN THE HALF-FILLED LANDAU-LEVEL- CHARGEON-FLUXON APPROACH

We have previously studied the phase structure at finite temperatures of the Chem-Simons (CS) gauge theory coupled with fermions by using la ttice gauge theory. In this paper, we formulate the ''chargeon-fluxon' ' representation of electrons and use it to reinvestigate the phenomen on of particle-flux separation (PFS) of electrons in the half-filled L andau level. We start with a lattice system of fermions interacting wi th a CS gauge field, and introduce two slave operators named chargeon and fluxon that carry the CS charge and flux, respectively. The origin al fermion, the composite fermion of Jain, is a composite of a chargeo n and a fluxon. We further rewrite the model by introducing an auxilia ry link field, the phase of which behaves as a gauge field gluing char geons and fluxons. Then we study a confinement-deconfinement transitio n of that gauge field by using the theory of separation phenomena as i n the previous paper. The residual four-Fermi interactions play an imp ortant role to determine the critical temperature T-PFS,, below which the PFS takes place, The new representation has some advantages; (1) I t allows a field-theoretical description also for the flux degrees of freedom. (2) It has a close resemblance to the slave-boson or slave-fe rmion 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 o pens a way to understand the two typical separation phenomena in stron gly correlated electron systems in a general and common setting.