Numerical Study on the Spin Gap of the Kagome Lattice Antiferromagnet

Abstract

The spin gap issue of the kagome lattice antiferromagnet is invesitigated by the finite size scaling analysis applied for the energy spectrum of the rhombic clusters calculated by the numerical exact diagonalization. The conclusion is that the kagome lattice antiferromagnet is gapless, as well as the triangular lattice one.

Spontaneous Multipole Ordering by Local Parity Mixing

“…For instance, there are several f -electron materials possessing the lattice structures without local inversion symmetry, such as ferromagnetic superconductors UGe 2 , [28][29][30] URhGe, [31][32][33] and UCoGe, [34][35][36] the zig-zag chain compounds LnM 2 Al 10 (Ln=Ce, Nd, Gd, Dy, Ho, and Er; M=Fe, Ru, and Os), [37][38][39][40][41][42][43][44] the distorted honeycomb compounds αand β-YbAlB 4 , [45][46][47] and the diamond-structure compounds RT 2 X 20 (R=Pr, La, Yb, and U, T =Fe, Co, Ti, V, Nb, Ru, Rh, and Ir, and X =Al and Zn). [48][49][50][51][52][53][54][55][56][57][58][59] Although these materials can be candidates for unusual odd-parity multipole ordering through the local parity mixing, their properties have not been studied from such a viewpoint. In order to stimulate experiments and theories, it is important to clarify the microscopic mechanism for odd-parity multipole ordering.…”