Confinement of spin and charge in high-temperature superconductors.

By exploiting the internal gauge-invariance intrinsic to a spin-charge separated electron, we show that such degrees of freedom must be confined in two-dimensional superconductors experiencing strong inter-electron repulsion. We also demonstrate that incipient confinement in the normal state can prevent chiral spin-fluctuations from destroying the cross-over between strange and psuedo-gap regimes in under-doped high-temperature superconductors. Last, we suggest that the negative Hall anomaly observed in these materials is connected with this confinement effect. PACS Indices: 74.20.De, 74.20.Mn, 74.20.Kk, 71.27.+a † Laboratoire associe au CNRS. 1 The electronic conduction in high-temperature superconductors is characterized by quasi two dimensionality and strong inter-electron repulsion. Motivated by the corresponding situation in one dimension, Anderson proposed early on that the correlated electron in these materials factorizes into independent spin and charge degrees of freedom as a result. The abelian gauge-field theory formulation of the t − J model for strongly interacting two-dimensional (2D) electrons provides an elegant expression of these ideas. The electron field in such theories is divided up into fermionic spin and bosonic charge parts, ciσ = fiσb † i , where the internal gauge invariance (fiσ, bi) → e i(fiσ, bi) enforces the constraint