Strain Effect on Electronic Structure and Work Function in α-Fe2O3 Films

Abstract

We investigate the electronic structure and work function modulation of α-Fe2O3 films by strain based on the density functional method. We find that the band gap of clean α-Fe2O3 films is a function of the strain and is influenced significantly by the element termination on the surface. The px and py orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied dz2 orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for pz orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing) under compressive (tensile) strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because pz orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

Origin of High-Efficiency Photoelectrochemical Water Splitting on Hematite/Functional Nanohybrid Metal Oxide Overlayer Photoanode after a Low Temperature Inert Gas Annealing Treatment

“…The unit cell was sampled using a Γ-centered k -point grid of 8 × 8 × 8. From our calculations, the lowest energy magnetic ordering was determined to be antiferromagnetic as seen in neutron diffraction studies and previous DFT work. ,,− …”

“…From our calculations, the lowest energy magnetic ordering was determined to be antiferromagnetic as seen in neutron diffraction studies and previous DFT work. 35,38,61−63…”

Unravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques

“…63 Moreover, the measured work functions of Co 3 O 4 ( φ 1 ), Co 2 FeO 4 ( φ 2 ), CoFe 2 O 4 ( φ 3 ) and Fe 2 O 3 ( φ 4 ) are 5.6, 6.2, 6.3 and 6.1 eV, respectively. 64,65 The work function plays a significant role in the electrocatalysis, which is discussed in the electrochemical part of this article. 66…”

Rolling dopant and strain in Y-doped BiFeO3 epitaxial thin films for photoelectrochemical water splitting

“…3, a thickness of 145 nm corresponds to an out-of-plane parameter of 3.905 Å equal to the STON substrate lattice constant, thickness for which a Y-BFO film could be considered completely relaxed. This value was used to evaluate the strain percent defined as ( a  −  a o )/ a o where a o is the experimental lattice constant without strain, and a is the experimental lattice constant under compressive or tensile strain 32 . The strain percent values are presented in the last column of Table 1.…”