Static spin susceptibility in magnetically ordered states

Abstract

We report that special care is needed when longitudinal magnetic susceptibility is computed in a magnetically ordered phase, especially in metals. We demonstrate this by studying static susceptibility in both a ferromagnetic and an antiferromagnetic state in the random phase approximation to the two-dimensional Hubbard model on a square lattice. In contrast to the case in the disordered phase, a first derivative of the chemical potential (or the density) with respect to a magnetic field does not vanish in a magnetically ordered phase when the field is applied parallel to the magnetic moment. This effect is crucial and should be included when computing magnetic susceptibility in the ordered phase, otherwise an unphysical result would be obtained. In addition, consequently the magnetic susceptibility becomes different when computed at a fixed density and a fixed chemical potential in the ordered phase. In particular, we cannot employ magnetic susceptibility at a fixed chemical potential to describe a system with a fixed density even if the chemical potential is tuned to reproduce the correct density.

19 pages, 8 figures

References in corpus (3)

• Theory of itinerant magnetic excitations in the SDW phase of iron-based superconductors
• Spin excitations in layered antiferromagnetic metals and superconductors
• Low-energy Spin Excitation in Coexistent Phase of Antiferromagnetism and d-wave Superconductivity

Cited by in corpus (4)

• The dynamical vertex approximation for many-electron systems with spontaneously broken SU(2)-symmetry
• Theoretical Study of Temperature Dependence of Spin Susceptibility in Anisotropic Itinerant Ferromagnets
• Spin and bond-charge excitation spectra in correlated electron systems near antiferromagnetic phase
• Anomaly of longitudinal spin susceptibility at superconducting instability inside a magnetic phase