First principles investigation of electron correlation and Lifshitz transition within iron polynitrides

Abstract

Metal poly-nitrogen compounds are gaining great interests as potential high energy density materials. Several iron polynitrides have been recently synthesized and investigated under high pressure (2018 Nature Communications 9 2756). In this work the electron correlations within these iron poly-nitrogen compounds were self-consistently determined, benchmarked with those obtained from linear response approach. Along with the increase of the concentration of nitrogen, the Coulomb interaction strengths show a monotonic decrease, where FeN and FeN2 are antiferromagnetic and the others are ferromagnetic. Then the electron correlation is studied along with the pressure, where the electrons are more delocalized as pressure becomes higher. One electronic topological transition was found for FeN2, owing to a breaking of symmetry of spin and a transition of magnetism induced by a structural change. The band structure, densities of states, Fermi surface and absorption spectra were calculated and discussed.

First‐Principles Calculations of Physical Properties and Stability of Orthorhombic FeN2 under High Pressure

“…[34][35][36] The U and J values are given as 4.565 and 0.853 eV for Fe-d orbital, respectively, which have been verified to show a good description of the structural and electronic properties for FeN 2 . [37] The electron-ion interactions are described by projector-augmented wave (PAW) potentials. [38] The self-consistent total energy difference and the convergence criterion for forces on atoms are set as 1 Â 10 À5 eV atom À1 and 0.02 eV Å À1 , respectively.…”

An Ab Initio Investigation of CdSnN2Under Uniaxial Compressions

“…As shown in literatures, in some cases, applying stress or strain can effectively manipulate the electronic structure and mechanical properties of materials. [ 21–28 ] As for the II–IV–V 2 ceramics, it was recently discovered that XGeN 2 (X = Mg,Zn,Cd) and MSnN 2 (M = Mg,Zn) transit from structure to Pnma structure under uniaxial compression along [100] direction at a certain value, [ 19,29,30 ] where MgGeN 2 and MgSnN 2 can stabilize at the newly discovered Pnma phase after fully removing the compression. Based on this, thickness‐dependent thin films were constructed and studied on their electronic properties.…”

Electronic and optical properties of metal decorated graphitic carbon nitride M/g‐C3N4 (M = K, Ca, Ga, Ni, Cu): A theoretical study

“…The authors also demonstrated that the band structure of iron‐doped g‐C 3 N 4 is dependent on the doping concentration. [ 6 ] Although there have been many studies on the structure and characteristics of the metal doped g‐C 3 N 4 systems, there are still some concerns, such as the causes and effects of metals on photogenerated carriers’ separation and the electron excitation mechanism. In this work, we present detailed studies on the influence of single metal (K, Ca, Ga, Cu, Ni) doping on the electronic and optical properties of g‐C 3 N 4 .…”