  Exotic quantum states could be induced due to the interplay of various
degrees of freedom such as charge, spin, orbital, and lattice. Recently, a
novel short-ranged charge order (CO) was discovered deep inside the
antiferromagnetic phase of a correlated Kagome magnet FeGe. Since the
spin-polarization is significantly enhanced in the CO state, magnetism may play
an important role. However, its short-ranged nature hinders the precise
identification of CO properties, and its mechanism is still controversial.
Here, we report the observation of a long-ranged CO in high-quality FeGe
samples, in contrast to the previously reported short-ranged ones. Moreover,
the distorted 2*2*2 CO superstructure could now be precisely refined, which is
characterized by a strong dimerization along the c-axis of 1/4 of the Ge1-sites
in the Fe3Ge layers. Our results provide strong support to the recent
theoretical prediction (arXiv:2304.01604), where the CO in FeGe is driven by
saving magnetic exchange energies via such dimerization. Consequently, the
enhancement of spin-polarization and the previously observed short-ranged CO
can be understood. Our experiments combined with the theory, have provided a
comprehensive understanding of the puzzling CO behavior in FeGe, and
established a novel charge order mechanism conspired by magnetism and lattice,
different from conventional charge density wave mechanisms.
