Spin density wave in the bilayered nickelate La3Ni2O7−δ at ambient pressure
Xiao-Sheng Ni, Yuyang Ji, Lixin He, Tao Xie, Dao‐Xin Yao, Meng Wang, Kun Cao
Abstract
Abstract The recent discovery of high-temperature superconductivity in high-pressurized La 3 Ni 2 O 7− δ has garnered significant attention. Using density functional theory, we investigate the magnetic properties of La 3 Ni 2 O 7− δ at ambient pressure. Our calculations suggest that with δ = 0, the double spin stripe phase is favored as the magnetic ground state. Oxygen vacancies may effectively turn nearest Ni spins into charge sites. Consequently, with moderate δ values, our theoretical magnetic ground state exhibits characteristics of both double spin stripe and spin-charge stripe configurations, providing a natural explanation to reconcile the seemingly contradictory experimental findings that suggest both the configurations as candidates for the spin-density-wave phase. With higher δ values, we anticipate the ground state to become a spin-glass-like noncollinear magnetic phase with only short-range order. The oxygen vacancies are expected to significantly impact the magnetic excitations and the transition temperatures T S D W . Notably, the magnetic ordering also induces concomitant charge ordering and orbital ordering, driven by spin-lattice coupling under the low symmetry magnetic order. We further offer a plausible explanation for the experimental observations that the measured T S D W appears insensitive to the variation of samples and the lack of direct evidence for long-range magnetic ordering.