Double exchange model on triangular lattice: Non-coplanar spin configuration and phase transition near quarter filling

Abstract

Unconventional anomalous Hall effect in frustrated pyrochlore oxides is originated from spin chirality of non-coplanar localized spins, which can also be induced by the competition between ferromagnetic (FM) double exchange interaction J H and antiferromagnetic superexchange interaction J AF . Here truncated polynomial expansion method and Monte Carlo simulation are adopted to investigate the above model on two-dimensional triangular lattice. We discuss the influence of the range of FM-type spin-spin correlation and strong electron-spin correlation on the truncation error of spin-spin correlation near quarter filling. Two peaks of the probability distribution of Email address: zhanggp96@ruc.edu.cn (G. P. Zhang) Preprint submitted to Physica B January 2, 2018 spin-spin correlation in non-coplanar spin configuration clearly show that non-coplanar spin configuration is an intermediate phase between FM and 120-degree spin phase. Near quarter filling, there is a phase transition from FM into non-coplanar and further into 120-degree spin phase when J AF continually increases. Finally the effect of temperature on magnetic structure is discussed.