Spatial distribution of transferred charges across the heterointerface between perovskite transition metal oxides LaNiO3 and LaMnO3

Abstract

To investigate the interfacial charge-transfer phenomena between perovskite transition metal oxides LaNiO3 (LNO) and LaMnO3 (LMO), we have performed in situ x-ray absorption spectroscopy (XAS) measurements on LNO/LMO multilayers. The Ni-L2,3 and Mn-L2,3 XAS spectra clearly show the occurrence of electron transfer from Mn to Ni ions in the interface region. Detailed analysis of the thickness dependence of these XAS spectra has revealed that the spatial distribution of the transferred charges across the interface is significantly different between the two constituent layers. The observed spatial distribution is presumably described by the charge spreading model that treats the transfer integral between neighboring transition metal ions and the Coulomb interaction, rather than the Thomas–Fermi screening model.

Interfacial Charge Engineering in Ferroelectric‐Controlled Mott Transistors

“…The values extracted from XPS/XAS studies only account for about 70% of the interpolated value, which is understandable as those techniques can penetrate beyond the interfacial atomic layer. The measurements are thus probing a spatially weighted average of the valence change, which can extend over a length scale on the order of L CS from the interface . The spatial variation of charge transfer is clearly demonstrated in the calculations of superlattices with a larger periodicity.…”

“…In this scenario, to achieve a tailored carrier density profile in SNNO, it is critical to have a strong overlap between the charge‐transfer region from the SNNO/LSMO interface and the charge screening region from the PZT/SNNO interface. Previous dynamic mean field theory studies of ABO 3 ‐type correlated oxide superlattices have shown that the spatial mobile electron density variation on the B ‐site cations depends critically on the relative strength of electron hopping energy and the Coulomb interaction . The characteristic length for charge transfer is the Coulomb charge screening length, defined as , where ε 0 , t , and a are the vacuum permittivity, transfer integral, and lattice parameter, respectively.…”

“…The SNNO layer thickness in the bilayer channels is thus approaching the charge‐transfer length. As the charge reconstruction at the SNNO/LSMO interface would lead to a smoothly varying background in the carrier density over a length scale that would extend beyond L CS , we expect the spatial density distribution from the PZT/SNNO interface in these samples to be strongly perturbed (Figure d), making the field effect modulation more effective.…”

Spatial coherence of the insulating phase in quasi-two-dimensional LaNiO3 films

“…2. Here, we focus on the Ni-2p XAS spectra at the Ni-L 2 edge because the Ni-L 3 edge structure partially overlaps with the very strong La-M 4 absorption edge owing to the close proximity of the two energy levels 30,31 . In order to examine the valence of Ni ions in the thin films, the energy of Ni 3+ (871.9 eV) and Ni 2+ (870.3 eV) signals in perovskite nickelates 32 are indicated by solid lines.…”

Emergentc-axis magnetic helix in manganite-nickelate superlattices

“…Superlattices composed of manganites and nickelates are a paradigmatic venue for efforts to discover and understand emergent interface magnetism, motivated by the complex magnetic order and phase diagram of its bulk constituents [10,11]. In fact, this system harbors fascinating phenomena, such as exchange bias and interfacial electronic reconstructions [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Recently, a highly unusual magnetic coupling between ferromagnetic (LSMO) 9 layers was observed in [001]-oriented (La 2/3 Sr 1/3 MnO 3 ) 9 /(LaNiO 3 ) n [(LSMO) 9 /(LNO) n , n = 1 − 9], in which the coupling angle between (LSMO) 9 layers varies between zero and 130 • as a function of n ( Fig.…”