Magnetic phase diagram of the t-J model on the triangular lattice

SPOSETTI C. N.; TRUMPER A. .; MANUEL L. O.

Buenos Aires

Otro; XII Giambiagi School: Low dimensional condensed matter; 2010

Universidad Nacional de Buenos Aires

We study the magnetic phase diagram of the t-J model on a triangular lattice as a function of doping and J/t, using the slave fermion-Schwinger boson mean-field approximation. We find that the magnetic properties of the model depend crucially on the sign of the hopping integral t. For t > 0, we find an enhancement of antiferromagnetic correlations with doping, due to the synergy between exchange interactions and the kinetic energy of the dopedholes. In particular, at low doping and small J/t, a 120º Néel order of kinetic origin is stabilized; this phase is closely related with the antiferromagnetic Nagaoka phase recently proposed by Haerter and Shastry. On the other hand, for t < 0, the 120º Néel order disappears for very low doping, while there is a clear predominance of ferromagnetic correlations in a broad doping range: a Nagaoka ferromagnetic phase for small J/t and an incommensurate spiral phase for moderate values of J/t.