ARPES spectral functions and Fermi surface for La(1.86)Sr(0.14)CuO(4) compared with LDA+DMFT+Sk calculations

Slightly underdoped high-Tc system La(1.86)Sr(0.14)CuO(4) (LSCO) is studied by means of high energy high resolution angular resolved photoemission spectroscopy (ARPES) and combined computational scheme LDA+DMFT+Sk. Corresponding one band Hubbard model is solved via dynamical mean-field theory (DMFT), while model parameters needed are obtained from first principles within local density approximation (LDA). An "external" k-dependent self-energy Sk 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 (pi,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 (pi,0) point. The same behavior of spectral functions follows from theoretical calculations suggesting AFM origin of the pseudogap state.