Abstract
Strain control is one of the most promising avenues to search for new emergent phenomena in transition-metal-oxide films. Here, we investigate the strain-induced changes of electronic structures in strongly correlated LaNiO3 (LNO) films, using angle-resolved photoemission spectroscopy and the dynamical mean-field theory. The strongly renormalized eg-orbital bands are systematically rearranged by misfit strain to change its fermiology. As tensile strain increases, the hole pocket centered at the A point elongates along the kz-axis and seems to become open, thus changing Fermi-surface (FS) topology from three- to quasi-two-dimensional. Concomitantly, the FS shape becomes flattened to enhance FS nesting. A FS superstructure with Q1 = (1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q2 = (1/4,1/4,1/4) modulation, indicating that some instabilities are present in metallic LNO films. Charge disproportionation and spin-density-wave fluctuations observed in other nickelates might be their most probable origins.
Highlights
Strain control is one of the most promising avenues to search for new emergent phenomena in transition-metal-oxide films
In LNO films, the misfit strain will induce a change of Madelung potential, resulting in a different D28, which would be an origin of charge disproportionation (CD) in LNO films[28,30]
In this Letter, to investigate the systematic changes of electronic structures of LNO films under various misfit strains, we employed in situ angle-resolved photoemission spectroscopy (ARPES) and the dynamical mean-field theory (DMFT)
Summary
Strain control is one of the most promising avenues to search for new emergent phenomena in transition-metal-oxide films. M isfit strain has been a key control parameter to tune physical properties and to search for new emergent phenomena in transition-metal-oxide (TMO) films[1,2,3,4,5,6,7,8,9]. Lee et al claimed that the SDW order should appear due to Fermi-surface (FS) nesting by tuning effective hopping parameters between Ni 3d orbitals[31,32]. In spite of these intriguing theoretical predictions, there have been few experimental evidences for them. Misfit strain can be used as a tuning parameter to search for latent orders in TMO films
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