Quantum phase transitions in the S=1/2 distorted diamond chain

By means of the second derivative of the ground-state and first-excited energy, the quantum phase transitions (QPTs) for the distorted diamond chain (DDC) with ferromagnetic and antiferromagnetic frustrated interactions and the trimerized case are investigated, respectively. Our results show the plentiful quantum phases owing to the spin interaction competitions in the model. Meanwhile, by using the transfer-matrix renormalization-group technique, we study the two-site thermal entanglement of the DDC model in the thermodynamic limit for a further understanding of the QPTs.

National Basic Research Program of China G2009CB929300 National Natural Science Foundation of China 60521001 60776061This work was supported by the National Basic Research Program of China (973 Program) under Grant No. G2009CB929300 and the National Natural Science Foundation of China under Grants No. 60521001 and No. 60776061.