Molecular Spin Dynamics Analysis of Complex Magnetic Structure on the FCC Lattice in Itinerant Electron System

The magnetic structure of the Hubbard model on the fcc lattice with competing magneticinteractions has been investigated by means of the Molecular Spin Dynamics (MSD) method. For the Coulomb interaction strength U/|t| = 8, the MSD yields the ferromagnetism for electron number n from 2.0 to 1.2, complex ferrimagnetic structures for n from 1.2 to 0.8, complex anti- ferromagnetic structures between n = 0.8 and 0.6, and the paramagnetic state below n = 0.60. By making use of the Fourier analysis, it is found that the 3Q multiple spin density waves with triple Q wave vectors, the 2Q multiple spin density waves with double Q wave vectors, and a complex antiferromagnetic structure with amplitude modulation are realized for n ≈ 0.90,n ≈ 0.75, and n ≈ 0.70, respectively.