Double Helix Magnetic Order in CrAs with MnP-Type Crystal Structure

The transition metal pnictide CrAs exhibits superconductivity in the vicinity of a helimagnetic phase, where it has been found that propagation vector is parallel to c axis and magnetic moments lie ab plane. Here we use initio calculations study interactions material. Mapping onto Heisenberg Hamiltonian, calculate exchanges by using LDA+U unveil origin frustration. Finally, reproduce double helix order with Q = (0, 0, 0.456) obtain temperature TN through Monte-Carlo simulations specific heat. Due limitations Hamiltonian for itinerant systems, theoretical underestimated experimental value pure CrAs. However, our results are good agreement those alloy CrAs0.5Sb0.5 belonging same space group, showing result can describe this material class.