Rich properties of systems with strongly correlated electrons, such as transition metal oxides, is largely connected with an interplay of different degrees of freedom in them: charge, spin, orbital ones, as well as crystal lattice. Specific and often very important role is played by orbital degrees of freedom. In this comment I will shortly summarize the main concepts and discuss some of the well-known manifestations of orbital degrees of freedom, but will mostly concentrate on a recent development in this field.
Categories: cond-mat.str-el cond-mat.mtrl-sci