Substantial hole doping has been achieved in (La, Sr, Ca)14Cu24O41 compounds with CuO2 chain and Cu2O3 ladder building blocks. Holes enter the structural units with larger O/Cu ratios which are the CuO2 chains. The ladders remain undoped and magnetically inert due to a large spin gap. The moments in the undoped chains interact weakly, and every hole added creates a nonmagnetic CuO2 unit and decreases the resistivity. At the maximum hole concentration [Formula presented] the residual moments form a singlet ground state possibly due to dimerization with an excitation gap of 140 K to the triplet state.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)