Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quant...Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quantum materials,contrast inversion in scanning tunneling microscopy images,observed between opposite bias polarity,serves as a hallmark of the charge density wave.However,in itinerant ferromagnetic systems,charge density wave formation competes with magnetism:A charge density wave order typically reduces the density of states at the Fermi level,while the Stoner criterion for spontaneous spin polarization requires a high density of states at Fermi level.Therefore,direct real-space observation of such polarity-dependent contrast inversion in ferromagnetic materials remains elusive and experimentally challenging.Here,we demonstrate the observation of a charge density wave in itinerant ferromagnet Fe_(5)GeTe_(2) associated with √3×√3 superlattice,revealed through polarity-dependent scanning tunneling microscopy imaging.Importantly,we observe a gap-like dip at the Fermi level in tunneling spectra,serving additional evidence for the emergence of charge density wave in Fe_(5)GeTe_(2).Interestingly,the strength of charge modulation can be systematically tuned by Fe1 vacancies and impurities,while the spectroscopic intensity shows a high sensitivity to surface degradation.Our finding provides an inspiring insight to charge density wave on the van der Waals ferromagnetic materials.展开更多
基金the support by the National Key Research and Development Program of China(No.2024YFA1408104(H.T.Y.))the National Natural Science Foundation of China(Nos.92365203(H.T.Y.),U24A6002(H.T.Y.),12104238(Y.F.L.),and U21A2085(Z.Y.L.(Zhongyuan Liu))+2 种基金Innovation Program for Quantum Science and Technology(No.2021ZD0302502(H.T.Y.))the Natural Science Foundation of Jiangsu Province(Nos.BK20253012(H.T.Y.),BK20233001(H.T.Y.),BK20243011(H.T.Y.),and BK20253027(Y.F.L.))the support from the Jiangsu Key Laboratory of Artificial Functional Materials.
文摘Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quantum materials,contrast inversion in scanning tunneling microscopy images,observed between opposite bias polarity,serves as a hallmark of the charge density wave.However,in itinerant ferromagnetic systems,charge density wave formation competes with magnetism:A charge density wave order typically reduces the density of states at the Fermi level,while the Stoner criterion for spontaneous spin polarization requires a high density of states at Fermi level.Therefore,direct real-space observation of such polarity-dependent contrast inversion in ferromagnetic materials remains elusive and experimentally challenging.Here,we demonstrate the observation of a charge density wave in itinerant ferromagnet Fe_(5)GeTe_(2) associated with √3×√3 superlattice,revealed through polarity-dependent scanning tunneling microscopy imaging.Importantly,we observe a gap-like dip at the Fermi level in tunneling spectra,serving additional evidence for the emergence of charge density wave in Fe_(5)GeTe_(2).Interestingly,the strength of charge modulation can be systematically tuned by Fe1 vacancies and impurities,while the spectroscopic intensity shows a high sensitivity to surface degradation.Our finding provides an inspiring insight to charge density wave on the van der Waals ferromagnetic materials.
