Effects of direct mixing of CDW and SDW states in mixed-metal MX-chains

The competition between a charge-density-wave (CDW) state and a spin-density-wave (SDW) state is theoretically discussed, with Pd-Ni mixed-metal MX-chains as the target materials. The strongest emphasis is placed on a non-trivial new state, namely, the Pd 3+ with a finite local spin on it. Using mean-field and quantum Monte-Carlo calculations, we find that this state is realized by the inclusion of, at least, more than 50% of Ni sites and explains almost all the experimental facts qualitatively.