An electronic origin of charge order in infinite-layer nickelates

Abstract

Abstract A charge order (CO) with a wavevector $${{{{{{{\bf{q}}}}}}}}\simeq \left(\frac{1}{3},\, 0,\, 0\right)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>q</mml:mi> <mml:mo>≃</mml:mo> <mml:mfenced> <mml:mrow> <mml:mfrac> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:mfrac> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> 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, $${{{{{{{\bf{q}}}}}}}}=\left(\frac{1}{3},\, 0,\, 0\right)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>q</mml:mi> <mml:mo>=</mml:mo> <mml:mfenced> <mml:mrow> <mml:mfrac> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:mfrac> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> 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.

Topics & Concepts