Correlation functions and excitation spectrum of the frustrated ferromagnetic spin-1/2 chain in an external magnetic field

摘要

Magnetic field effects on the one-dimensional frustrated ferromagnetic chainare studied by means of effective field theory approaches in combination withnumerical calculations utilizing Lanczos diagonalization and the density matrixrenormalization group method. The nature of the ground state is shown to changefrom a spin-density-wave region to a nematic-like one upon approaching thesaturation magnetization. The excitation spectrum is analyzed and the behaviorof the single spin-flip excitation gap is studied in detail, including theemergent finite-size corrections.