The kagome metal FeGe provides a rich platform for understanding the mechanisms behind competing orders,as it exhibits charge order(CO)emerging deep within the antiferromagnetic phase.To investigate the intrinsic orig...The kagome metal FeGe provides a rich platform for understanding the mechanisms behind competing orders,as it exhibits charge order(CO)emerging deep within the antiferromagnetic phase.To investigate the intrinsic origin of this behavior,we examine the evolution of the low-energy electronic structure across the phase transition in annealed FeGe samples using angleresolved photoemission spectroscopy.We find no evidence supporting a conventional nesting mechanism,such as Fermi surface nesting or van Hove singularities.However,we observe two notable changes in the band structure:an electron-like band around the K point and another around the A point,both shifting upward in energy when CO forms.These findings are consistent with our density-functional theory calculations,which suggest that the charge order in FeGe is primarily driven by magnetic energy savings due to a lattice distortion involving Ge1-dimerization.Our results provide photoemission evidence supporting this novel mechanism for CO formation in FeGe,in contrast to the conventional nesting-driven mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12174362,11888101,11790312,92065202,12474142,and 12174365)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302803)the New Cornerstone Science Foundation.Part of this research used Beamline 03U of the Shanghai Synchrotron Radiation Facility,which is supported by the ME2 project from the National Natural Science Foundation of China(Grant No.11227902).
文摘The kagome metal FeGe provides a rich platform for understanding the mechanisms behind competing orders,as it exhibits charge order(CO)emerging deep within the antiferromagnetic phase.To investigate the intrinsic origin of this behavior,we examine the evolution of the low-energy electronic structure across the phase transition in annealed FeGe samples using angleresolved photoemission spectroscopy.We find no evidence supporting a conventional nesting mechanism,such as Fermi surface nesting or van Hove singularities.However,we observe two notable changes in the band structure:an electron-like band around the K point and another around the A point,both shifting upward in energy when CO forms.These findings are consistent with our density-functional theory calculations,which suggest that the charge order in FeGe is primarily driven by magnetic energy savings due to a lattice distortion involving Ge1-dimerization.Our results provide photoemission evidence supporting this novel mechanism for CO formation in FeGe,in contrast to the conventional nesting-driven mechanisms.
