Portal de Periódicos da CAPES

Influence of gauge-field fluctuations on composite fermions near the half-filled state

1995; American Physical Society; Volume: 51; Issue: 16 Linguagem: Inglês

10.1103/physrevb.51.10779

1095-3795

Yong Baek Kim, Patrick A. Lee, Xiao-Gang Wen, P. C. E. Stamp,

Quantum many-body systems

Taking into account the transverse gauge-field fluctuations, which interact with composite fermions, we examine the finite-temperature compressibility of the fermions as a function of an effective magnetic field \ensuremath{\Delta}B=B-2${\mathit{n}}_{\mathit{e}}$hc/e (${\mathit{n}}_{\mathit{e}}$ is the density of electrons) near the half-filled state. It is shown that, after including the lowest-order gauge-field correction, the compressibility becomes \ensuremath{\partial}n/\ensuremath{\partial}\ensuremath{\mu}\ensuremath{\propto}${\mathit{e}}_{\mathit{c}}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\Delta}}\mathrm{\ensuremath{\omega}}}$/2T[1 +[A(\ensuremath{\eta})/(\ensuremath{\eta}-1)](\ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$${)}^{2/(1+\mathrm{\ensuremath{\eta}})}$/T] for T\ensuremath{\ll}\ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$, where \ensuremath{\Delta}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$=e\ensuremath{\Delta}B/mc. Here we assume that the interaction between the fermions is given by v(q)=${\mathit{V}}_{0}$/${\mathit{q}}^{2\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\eta}}}$ (1\ensuremath{\le}\ensuremath{\eta}\ensuremath{\le}2), where A(\ensuremath{\eta}) is an \ensuremath{\eta}-dependent constant. This result can be interpreted as a divergent correction to the activation energy gap and is consistent with the divergent renormalization of the effective mass of the composite fermions.