MAGNETIC POLARONS IN MAGNETIC LOW CARRIER DENSITY SYSTEMS

In magnetic low carrier density systems, in addition to the strong intra-atomic correlation, a strong correlation due to the long-range Coulomb interaction becomes important, causing a tendency to Wigner crystal or liquid system. In magnetic systems, the tendency to localization is further enhanced by magnetic polarization, and the magnetic polaron liquid and lattice are fairly easily formed. This is most clearly seen in CeP and CeAs; a detailed description is given in this paper. A weak Gamma(8) hole magnetic polaron is formed in a liquid state even at room temperature. The population of the magnetic polaron decreases with decreasing population of 4f Gamma(8) but persists even at the lowest temperatures. An applied field and pressure change the weak magnetic polaron liquid to a strong magnetic polaron lattice with nearly saturated moment.