High-field magnetic resonance of spinons and magnons in the triangular lattice S=1/2 antiferromagnet Cs2CuCl4

作者：Smirnov A I^*; Soldatov T A; Povarov K Yu; Shapiro A Ya

来源：Physical Review B, 2015, 91(17): 174412.

DOI：10.1103/PhysRevB.91.174412

The electron spin resonance doublet indicating the width of the two-spinon continuum in a spin-1/2 triangular lattice Heisenberg antiferromagnet Cs2CuCl4 was studied in high magnetic field. The doublet was found to collapse in a magnetic field of one-half of the saturation field. The collapse of the doublet occurs via vanishing of the high-frequency component in a qualitative agreement with the theoretical prediction for the S = 1/2 chain. The field of the collapse is, however, much lower than expected for the S = 1/2 chain. This is proposed to be due to the destruction of frustration of interchain exchange bonds in a magnetic field, which restores the 2D character of this spin system. In the saturated phase the mode with the Larmor frequency and a much weaker mode downshifted for 119 GHz are observed. The weak mode is of exchange origin; it demonstrates a positive frequency shift at heating corresponding to the repulsion of magnons in the saturated phase.

• 出版日期2015-5-13