Many microscopic models with the interaction between the next-nearest neighbors as a key parameter for cuprate physics have inspired us to study the diagonal superexchange interaction in a ${\mathrm{CuO}}_2$ layer. Our investigation shows that models with extended hopping provide a correct representation of magnetic interactions only in a hypothetical square ${\mathrm{CuO}}_2$ layer, where the diagonal superexchange interaction with the next-nearest neighbors always has an antiferromagnetic (AFM) nature. The conclusions are based on the symmetry prohibition on the ferromagnetic contribution to the diagonal superexchange between the next-nearest neighbors for a simple square ${\mathrm{CuO}}_2$ layer rather than for a real ${\mathrm{CuO}}_2$ layer, where diagonal AFM superexchange may be overestimated. We also discuss the reasons for magnetic frustration effects and high sensitivity of spin nanoinhomogeneity to square symmetry breaking.

Close

PrevNext

View figure in article

• Exchange interaction
• Magnetic coupling
• Magnetic interactions
• Pairing mechanisms
• Structural properties
• Cuprates
• Methods in magnetism
• Spin lattice models