Chapter 4 Geometrical frustration

摘要: Publisher Summary This chapter discusses percolation theory as well spin-glass phenomena, the former of which is used to understand subjects diverse fluid flow in porous media electronic transport granular metals. The central role magnetic models for developing ideas condensed matter derives from unique attributes materials: (1) variability size and dimensionality fundamental degree freedom, effective atomic spin. dimensionality, n , can be 1 Ising, 2 (x-y) or 3 (Heisenberg) continuous spin degrees freedom. Low values lead enhanced quantum effects, (2) spin-spin interactions. These include dipole-dipole coupling, direct exchange, indirect super itinerant anisotropic exchange. range these interactions extend beyond nearest neighbor distances, anisotropic, leading low spatial (3) ability couple directly individual spins with field.