Entanglement in the Heisenberg spin chain with multiple interaction

The ground state and thermal entanglement of a Heisenberg spin chain in the presence of the multiple coupling interaction (type of XZX+YZY and type of XZY−YZX) is investigated. It is found that the role of the type of XZY−YZX interaction to the entanglement is identical to the Dzyaloshinsky-Moriya interaction. For a XZX+YZY type three-site interaction, the results show that this interaction can excite and enhance the entanglement even at the higher temperature.