First principles vs second principles: Role of charge self-consistency in strongly correlated systems

Abstract

First principles approaches have been successful in solving many-body Hamiltonians for real materials to an extent when correlations are weak or moderate. As the electronic correlations become stronger often embedding methods based on first principles approaches are used to better treat the correlations by solving a suitably chosen many-body Hamiltonian with a higher level theory. Such combined methods are often referred to as second principles approaches. At such level of the theory the self energy, i.e. the functional that embodies the stronger electronic correlations, is either a function of energy or momentum or both. The success of such theories is commonly measured by the quality of the self energy functional. However, self-consistency in the self-energy should, in principle, also change the real space charge distribution in a correlated material and be able to modify the electronic eigenfunctions, which is often undermined in second principles approaches. Here we study the impact of charge self-consistency within two example cases: TiSe${}_2$, a three-dimensional charge-density-wave candidate material, and CrBr${}_3$, a two-dimensional ferromagnet, and show how real space charge re-distribution due to correlation effects taken into account within a first principles Green's function based many-body perturbative approach is key in driving qualitative changes to the final electronic structure of these materials.

10 pages, 4 figures

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Cited by in corpus (14)

• QS$G\hat{W}$: Quasiparticle Self consistent $GW$ with ladder diagrams in $W$
• Paramagnetic Electronic Structure of CrSBr: Comparison between Ab Initio GW Theory and Angle-Resolved Photoemission Spectroscopy
• Excitons in Bulk and Layered Chromium Tri-Halides: From Frenkel to the Wannier-Mott Limit
• A Theory for Colors of Strongly Correlated Electronic Systems
• Beyond quasi-particle self-consistent $GW$ for molecules with vertex corrections
• Lattice fluctuations, not excitonic correlations, mediated electronic localization in TiSe${}_2$
• Distinct Magneto-Optical Response of Frenkel and Wannier Excitons in CrSBr
• Multiphoton excitation and high harmonic generation in rectangular graphene quantum dot
• One-particle and excitonic band structure in cubic Boron Arsenide
• Deconstruction of the anisotropic magnetic interactions from spin-entangled optical excitations in van der Waals antiferromagnets
• Many body theory beyond GW : towards a complete description of 2-body correlated propagation
• Quasiparticle Description of Angle-Resolved Photoemission Spectroscopy for SrCuO2
• Excitons and Optical Response in Excitonic Insulator Candidate TiSe${}_2$
• Many-body description of two-dimensional van der Waals ferroelectric $\alpha -$In${}_2$Se${}_3$