Role of electron correlation and disorder on the electronic structure of layered nickelate (La$_{0.5}$Sr$_{0.5}$)$_2$NiO$_4$

Sakshi Bansal; R. K. Maurya; Asif Ali; B. H. Reddy; Ravi Shankar Singh

doi:10.1103/PhysRevMaterials.7.064007

paper

Role of electron correlation and disorder on the electronic structure of layered nickelate (La $_{0.5}$ Sr $_{0.5}$ ) $_{2}$ NiO $_{4}$

arXiv:2306.04154 · doi:10.1103/PhysRevMaterials.7.064007

Abstract

We investigate the role of electron correlation and disorder on the electronic structure of layered nickelate (La $_{0.5}$ Sr $_{0.5}$ ) $_{2}$ NiO $_{4}$ using core level and valence band photoemission spectroscopy in conjunction with density functional theory (DFT) and dynamical mean field theory (DMFT) calculations. Sr 3 $d$ and La 4 $d$ core level spectra exhibit multiple features associated with photoemission final state effects. An increase of unscreened features in the Sr 3 $d$ and La 4 $d$ core level spectra with lowering temperature suggests the reduction in density of states (DOS) at the Fermi level, $E_{F}$ . Valence band spectra collected using different photon energies reveal finite intensity at $E_{F}$ and overall spectra are well captured by DFT+DMFT. Strong renormalization of partially filled $e_{g}$ bands in DFT+DMFT result indicates strong correlation in this system. Mass enhancement factor, $m^{*} / m_{DFT} \sim$ 3, agrees well with values obtained from specific heat measurements. High resolution spectra in the vicinity of $E_{F}$ show monotonically decreasing spectral intensity with lowering temperature, which evolves to exhibit a Fermi cut-off at low temperatures indicating metallic character in contrast to insulating transport, suggesting Anderson insulating state. $∣ E - E_{F} ∣^{1/2}$ dependence of the spectral DOS and square root temperature dependence of spectral DOS at $E_{F}$ evidences the role of disorder in the electronic structure of (La $_{0.5}$ Sr $_{0.5}$ ) $_{2}$ NiO $_{4}$ .

To appear in Physical Review Materials

Role of electron correlation and disorder on the electronic structure of layered nickelate (La $_{0.5}$ Sr $_{0.5}$ ) $_{2}$ NiO $_{4}$

Abstract

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Role of electron correlation and disorder on the electronic structure of layered nickelate (La0.5​Sr0.5​)2​NiO4​

Abstract

References in corpus (8)

Cited by in corpus (3)

Role of electron correlation and disorder on the electronic structure of layered nickelate (La $_{0.5}$ Sr $_{0.5}$ ) $_{2}$ NiO $_{4}$