A ug 1 99 4 Theory of electron – hole asymmetry in doped CuO 2 planes

The magnetic phase diagrams, and other physical characteristics, of the hole– doped La2−xSrxCuO4 and electron–doped Nd2−xCexCuO4 high–temperature superconductors are profoundly different. Given that it is envisaged that the simplest Hamiltonians describing these systems are the same, viz. the t − t − J model, this is surprising. Here we relate these physical differences to their ground states’ single–hole quasiparticles, the spin distortions they produce, and the spatial distribution of carriers for the multiply–doped systems. As is well known, the low doping limit of the hole–doped material corresponds to ~k = ( 2 , π 2 ) quasiparticles, states that generate so–called Shraiman–Siggia long–ranged dipolar spin distortions via backflow. These