Magneto-electric operators in neutron scattering from electrons

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Materials Science

Background:

• Understanding magnetic interactions is crucial for materials science and quantum mechanics.
• Existing models often focus on parity-even operators like magnetic moments.
• The role of symmetry, particularly inversion symmetry, in magnetic interactions is a key area of research.

Purpose of the Study:

• To derive an exact expression for neutron-electron magnetic interactions.
• To incorporate novel magneto-electric operators, including spin anapole and orbital toroidal analogues.
• To explore magnetic interactions in systems lacking inversion symmetry.

Main Methods:

• Theoretical derivation of magnetic interaction expressions.
• Inclusion of parity-odd operators (spin anapole, orbital toroidal analogue).
• Simulation of neutron diffraction using experimental data from resonant x-ray Bragg diffraction on antiferromagnetic copper oxide.

Main Results:

• An exact expression for magnetic interaction was successfully derived.
• The derived expression includes spin anapole and orbital toroidal operators, valid in the absence of inversion symmetry.
• Simulations demonstrated the utility of the derived expressions in analyzing neutron diffraction data.

Conclusions:

• The study provides a more complete description of magnetic interactions, extending beyond conventional magnetic moments.
• The findings are particularly relevant for materials lacking inversion symmetry.
• The work offers new insights into the magnetic structure of antiferromagnetic materials like copper oxide.