ARPES spectral functions and Fermi surface for La1.86Sr0.14CuO4 compared with LDA + DMFT + Σk calculations

Abstract

Slightly underdoped high-Tc system La1.86Sr0.14CuO4 (LSCO) is studied by means of high energy high resolution angular resolved photoemission spectroscopy (ARPES) and combined computational scheme LDA+DMFT+Σ k . Corresponding one band Hubbard model is solved via dynamical meanfield theory (DMFT), while model parameters needed are obtained from first principles within local density approximation (LDA). An "external" k-dependent self-energy Σ k describes interaction of correlated electrons with antiferromagnetic (AFM) pseudogap fluctuations. Experimental and theoretical data clearly show "destruction" of the LSCO Fermi surface in the vicinity of the (π,0) point and formation of "Fermi arcs" in the nodal directions. ARPES energy distribution curves (EDC) as well as momentum distribution curves (MDC) demonstrate deviation of the quasiparticle band from the Fermi level around (π,0) point. The same behavior of spectral functions follows from theoretical calculations suggesting AFM origin of the pseudogap state.

A Continuous Time Quantum Monte Carlo as an Impurity Solver for Strongly Correlated System

“…For sampling, the various terms, we employ Metropolis' algorithm [50] to accept or reject the possible transitions. The number of Monte Carlo samples may have only the Monte Carlo error, which scales as 1 √ N with the samples [51]]. Let us define all the possible orders of configuration space C as, C ={ {..} , {τ 1 }, {τ 1 , τ 2 }, ..., {τ 1 , ..., τ n } } Which is the set of continuous imaginary time variables τ j .…”

ChemInform Abstract: Magnetic Mechanisms of Pairing in Strongly Correlated Electron System of Copper Oxides

“…That is why the correct band dispersion and spectral intensities for these systems cannot be obtained within LDA+DMFT. Natural extension of this method, LDA+cluster or cellular DMFT [14,15,16,17], LDA+DMFT+Σ k [18,19,20,21,22,23] and SDFT (spectral density functional theory) [24] provides momentum dependent self-energy and thus allow for the non-local correlations.…”

Pseudogap phase of high-Tc compounds described within the LDA+DMFT+Sigma approach

“…Crystal structure of Bi2212 [2], NCCO [4] and PCCO [5] has tetragonal symmetry with the space group I4/mmm, while LSCO has ortorhombically distorted structure Bmab [3]. For further crystallographic data used within our LDA+DMFT+Σ k approach see Refs.…”

“…Here we present an overview of our recent works Refs. [2,3,4,5] on LDA+DMFT+Σ k computational scheme applcations. This scheme is generalization of dynamical mean-field theory DMFT [6] and LDA+DMFT [7] (LDA -local density approximation) approach allowing to include non-local scale dependent effects.…”

“…Within LDA+DMFT+Σ k approach several high-T c prototype compounds e.g. hole doped Bi 2 Sr 2 CaCu 2 O 8−δ (Bi2212) [2] and La 2−x Sr x CuO 4 (LSCO) [3] as well as electron doped Nd 2−x Ce x CuO 4 (NCCO) [4] and Pr 2−x Ce x CuO 4 (PCCO) [5] were studied. Since most powerful experimental tool to access electronic properties of the pseudogap state is angular resolved photoemission spectroscopy (ARPES) [12,13,14] we performed comparison of LDA+DMFT+Σ k calculated spectral functions and Fermi surfaces with available ARPES quasiparticle bands and Fermi surface maps.…”