biostudies-literatureHu YScience and Technology Commission of Shanghai MunicipalityNational Natural Science Foundation of ChinaScience and Technology Commission of Shanghai Municipality (Shanghai Municipal Science and Technology Commission)National Natural Science Foundation of China (National Science Foundation of China)445https://www.ebi.ac.uk/biostudies/studies/S-EPMC8782872biostudies-literatureUnknown13(1)In itinerant magnetic systems, a spin density wave (SDW) state can be induced by Fermi surface nesting and electron-electron interaction. It may intertwine with other orders such as charge density wave (CDW), while their relation is still yet to be understood. Here via spin-polarized scanning tunneling microscopy, we directly observed long-range spin modulation on Cr(001) surface, which corresponds to the well-known incommensurate SDW of bulk Cr. It displays 6.0 nm in-plane period and anti-phase behavior between adjacent (001) planes. Meanwhile, we simultaneously observed the coexisting CDW with half the period of SDW. Such SDW/CDW have highly correlated domain structures and are in-phase. Surprisingly, the CDW displays a contrast inversion around a density-of-states dip at -22 meV, indicating an anomalous CDW gap opened below E_F. These observations support that the CDW is a secondary order driven by SDW. Our work is not only a real-space characterization of incommensurate SDW, but also provides insights on how SDW and CDW coexist.Nature communicationsReal-space observation of incommensurate spin density wave and coexisting charge density wave on Cr (001) surface.PMC878287211888101,1179031219JC141270292065202, 11961160717Yang WZhang THu YLi CDing SFeng DZhao DWang XWang HChen CfalseReal-space observation of incommensurate spin density wave and coexisting charge density wave on Cr (001) surface.In itinerant magnetic systems, a spin density wave (SDW) state can be induced by Fermi surface nesting and electron-electron interaction. It may intertwine with other orders such as charge density wave (CDW), while their relation is still yet to be understood. Here via spin-polarized scanning tunneling microscopy, we directly observed long-range spin modulation on Cr(001) surface, which corresponds to the well-known incommensurate SDW of bulk Cr. It displays 6.0 nm in-plane period and anti-phase behavior between adjacent (001) planes. Meanwhile, we simultaneously observed the coexisting CDW with half the period of SDW. Such SDW/CDW have highly correlated domain structures and are in-phase. Surprisingly, the CDW displays a contrast inversion around a density-of-states dip at -22 meV, indicating an anomalous CDW gap opened below E_F. These observations support that the CDW is a secondary order driven by SDW. Our work is not only a real-space characterization of incommensurate SDW, but also provides insights on how SDW and CDW coexist.2022-01-01T00:00:00Z2022 Jan2025-04-04T19:17:33.449Z2025-04-04T19:17:33.449ZS-EPMC87828723506412810.1038/s41467-022-28104-2