Evidence for intra-unit-cell magnetic order in Bi 2 Sr 2 CaCu 2 O 8 + δ

摘要: Polarized elastic neutron scattering measurements have been performed in the bilayer copper oxide system ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$, providing evidence for an intra-unit-cell magnetic order inside pseudogap state. That shows time reversal symmetry breaking that state as already reported ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ through dichroism circularly polarized photoemission experiments. The displays same characteristic features one previously monolayer ${\mathrm{HgBa}}_{2}{\mathrm{CuO}}_{4+\ensuremath{\delta}}$ and ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+\mathit{x}}$, demonstrating this genuine phase is ubiquitous of high temperature materials.