セミナー情報

第51回 原研・兵県大合同コロキウム

日時: 平成20年12月2日(火) 16:00〜
Date and time: 2nd Dec. (Wed.) 16:00〜
場所: SPring-8, 萌光館
Place: SPring-8, "HOUKOUKAN" seminar room
Title: Phase Diagram of the Triangular t-J Model with Multiple Spin Exchange in the Doped-Mott Region
講演者: 伏屋 雄紀 氏 (東京大学理学部物理)
Speaker: Dr. Yuki Fuseya (Department of Physics, University of Tokyo) 
Abstract:

Monolayer helium-three adsorbed on a graphite surface is one of the most ideal two-dimensional fermion system. In this system, He atoms localize at a certain density forming triangular lattice, the so-called 4/7 phase. The effective mass exhibits a divergence toward the density of the 4/7 phase (n=1), indicating the Mott transition. We can, therefore recognize this system for n<1 as the doped-Mott region. Recently, a mysterious double-peaked structure in the specific heat has been reported in the doped-Mott region of monolayer 3He. It is expected that the double-peak structure originates from the separation of the energy scale of spin and charge. There has been, however, no justification of this scenario and we have no theories which explain how and why such a "spin-charge separation" is realized in this system. In this work, we present a theoretical justification of the behavior of spin-charge separation in monolayer liquid 3He. We introduced an effective model; the t-J model with the multiple spin exchange (MSE) interaction. The ground states of this model are investigated by the exact diagonalization. We found a phase where the energy spectrum suggest the behavior of spin-charge separation generated by a competition between MSEs.