@inproceedings{oai:repo.qst.go.jp:00054876,
 author = {Tonegawa, T. and Okamoto, K. and Hikihara, T. and Sakai, T. and 坂井 徹},
 book = {Journal of Physics. Conference Series},
 issue = {1},
 month = {Apr},
 note = {We explore the ground-state phase diagram of the S = 1/2 two-leg ladder. The isotropic leg interactions J1,a and J1,b between nearest neighbor spins in the legs a and b, respectively, are different from each other. The xy and z components of the uniform rung interactions are denoted by Jr and ΔJr, respectively, where Δ is the XXZ anisotropy parameter. This system has a frustration when J1,aJ1,b < 0 irrespective of the sign of Jr. The phase diagrams on the Δ (0≤Δ<1) versus J1,b plane in the cases of J1,a = − 0.2 and J1,a = 0.2 with Jr = −1 are determined numerically. We employ the physical consideration, the level spectroscopy analysis of the results obtained by the exact diagonalization method and also the density-matrix renormalization-group method. It is found that the non-collinear ferrimagnetic (NCFR) state appears as the ground state in the frustrated region of the parameters. Furthermore, the direct-product triplet-dimer (TD) state in which all rungs form the TD pair is the exact ground state, when J1,a + J1,b = 0 and 0≤ Δ lesssim 0.83. The obtained phase diagrams consist of the TD, XY and Haldane phases as well as the NCFR phase.},
 pages = {012003-1--01203-8},
 publisher = {IOP Publishing},
 title = {Frustrated S = 1/2 Two-Leg Ladder with Different Leg Interactions},
 volume = {828},
 year = {2017}
}