Popis: |
Since the character of the low-lying spin excitations in a one-dimensional disordered system is still to some extent under debate, and the quasi-crystals can, in some sense, be said to fill the space between the disordered and periodic systems, the authors consider it of fundamental interest to study the character of the excited states in a one-dimensional deterministic aperiodic spin system. In contrast to the disordered case they find that the Thue-Morse aperiodic chain also has extended spin waves in the high-energy region. |