An electronic origin of charge order in infinite-layer nickelates

A charge order (CO) with a wavevector q ≃ 1 3 , 0 , 0 is observed in infinite-layer nickelates. Here we use first-principles calculations to demonstrate a charge-transfer-driven CO mechanism in infinite-layer nickelates, which leads to a characteristic Ni 1+ -Ni 2+ -Ni 1+ stripe state. For every three Ni atoms, due to the presence of near-Fermi-level conduction bands, Hubbard interaction on Ni- d orbitals transfers electrons on one Ni atom to conduction bands and leaves electrons on the other two Ni atoms to become more localized. We further derive a low-energy effective model to elucidate that the CO state arises from a delicate competition between Hubbard interaction on Ni- d orbitals and charge transfer energy between Ni- d orbitals and conduction bands. With physically reasonable parameters, q = 1 3 , 0 , 0 CO state is more stable than uniform paramagnetic state and usual checkerboard antiferromagnetic state. Our work highlights the multi-band nature of infinite-layer nickelates, which leads to some distinctive correlated properties that are not found in cuprates. Recent experiments reported charge order with a stripe pattern in parent compounds of infinite-layer nickelate superconductors. Chen et al. use first principles and effective model calculations to propose an electronic, charge-transfer-driven mechanism of the charge order.