Origin of "hot-spots" in the pseudogap regime of Nd(1.85)Ce(0.15)CuO(4): LDA+DMFT+Sigma_k study

TL;DR

This study uses an advanced theoretical approach combining LDA, DMFT, and Sigma_k to analyze the electronic structure of Nd(1.85)Ce(0.15)CuO(4), revealing the formation of hot-spots on the Fermi surface due to antiferromagnetic fluctuations.

Contribution

It introduces a generalized LDA+DMFT+Sigma_k scheme to accurately model pseudogap effects and hot-spot formation in electron-doped cuprates, providing insights beyond previous models.

Findings

Pronounced hot-spots are formed on the Fermi surface in NCCO.

Theoretical results agree well with ARPES experimental data.

Differences in hot-spot characteristics compared to Bi2212 are explained.

Abstract

Material specific electronic band structure of the electron-doped high-Tc cuprate Nd(1.85)Ce(0.15)CuO(4) (NCCO) is calculated within the pseudo gap regime, using the recently developed generalized LDA+DMFT+Sigma_k scheme. LDA/DFT (density functional theory within local density approximation) provides model parameters (hopping integral values, local Coulomb interaction strength) for the one-band Hubbard model, which is solved by DMFT (dynamical mean-field theory). To take into account pseudogap fluctuations LDA+DMFT is supplied with "external" k-dependent self-energy Sigma_k, which describes interaction of correlated conducting electrons with non-local Heisenberg-like antiferromagnetic (AFM) spin fluctuations responsible for pseudo gap formation. Within this LDA+DMFT+Sigma_k approach we demonstrate the formation of pronounced "hot-spots" on the Fermi surface (FS) map in NCCO, opposite to our recent calculations for Bi(2)Sr(2)CaCu(2)O(8-d) (Bi2212), which have produced rather extended region of FS "destruction". There are several physical reasons for this fact: (i) the "hot-spots" in NCCO are located closer to Brillouin zone center; (ii) correlation length of AFM fluctuations \xi is larger for NCCO; (iii) pseudogap potential \Delta is stronger, than in Bi2212. Comparison of our theoretical data with recent bulk sensitive high-energy angle-resolved photoemission (ARPES) data for NCCO provides good semiquantitative agreement. Based on that comparison alternative explanation of the van-Hove singularity at -0.3 eV is proposed. Optical conductivity both for Bi2212 and NCCO is also calculated within LDA+DMFT+Sigma_k and compared with experimental results, demonstrating satisfactory agreement.