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

Abstract

Magnetic field effects on the one-dimensional frustrated ferromagnetic chain are studied by means of effective field-theory approaches in combination with numerical calculations utilizing Lanczos diagonalization and the density matrix renormalization group method. The nature of the ground state is shown to change from a spin-density-wave region to a nematiclike one upon approaching the saturation magnetization. The excitation spectrum is analyzed, and the behavior of the single-spin-flip excitation gap is studied in detail, including the emergent finite-size corrections.