Masters Defense: Hano Sura

Nematic phase transition in the J_1-J_2 model

The two dimensional Heisenberg J_1-J_2 model is a frustrated magnetic system with a continuous set of magnetically ordered ground states in the J_1<2J_2 regime. Fluctuations, both quantum and thermal, break this degeneracy into one between two states of different nematic order. At finite temperature the long-range magnetic order breaks down, but the system can still order into a state with finite nematic order. This thesis has explored the effect of interactions between spin waves on the critical temperature of the nematic phase transition through a mean field approximation of the interaction term.