Understanding the Kondo resonance in the d-CoPc/Au(111) adsorption system

Abstract

By combining the density functional theory (DFT) and a hierarchical equations of motion (HEOM) approach, we investigate the Kondo phenomena in a composite system consisting of a dehydrogenated cobalt phthalocyanine molecule (d-CoPc) adsorbed on an Au(111) surface. DFT calculations are performed to determine the ground-state geometric and electronic structures of the adsorption system. It is found that the singly occupied dz(2) orbital of Co forms a localized spin, which could be screened by the substrate conduction electrons. This screening leads to the prominent Kondo features as observed in the scanning tunneling microscopy experiments. We then employ the HEOM approach to characterize the Kondo correlations of the adsorption system. The calculated temperature-dependent differential conductance spectra and the predicted Kondo temperature agree well with the experiments, and the universal Kondo scaling behavior is correctly reproduced. This work thus provides important insights into the relevant experiments, and it also highlights the applicability of the combined DFT+HEOM approach to the studies of strongly correlated condensed matter systems.

Surface chemistry of porphyrins and phthalocyanines

“…6.2). The Kondo effect [662] observed for this structure (while no Kondo effect was observed for intact CoPc) indicated reduced Co-Au coupling [350,530,669]. Similar decoupling experiments were performed with partially dehydrogenated CoPc at monoatomic steps on Au(1 1 1) [530,670].…”

HEOM‐QUICK: a program for accurate, efficient, and universal characterization of strongly correlated quantum impurity systems

“…The HEOM‐QUICK program has been utilized in conjunction with DFT programs such as the Vienna ab initio simulation package (VASP) to realize first‐principles‐based simulation on magnetic molecular impurities. With the present HEOM‐QUICK code, a DFT + HEOM simulation proceeds as follows . First the geometric and electronic structures of the magnetic impurity system are calculated with DFT methods.…”

“…In the pioneering STM experiment performed by Zhao et al, it has been found that CoPc molecules absorbed on Au (111) surface does not exhibit Kondo phenomenon; while Kondo signature is clearly observed with the eight edge hydrogen atoms on the four benzene rings cut away from the CoPc molecule. The Kondo effect of a dehydrogenated CoPc (d‐CoPc) molecule absorbed on Au (111) surface has been investigated by combing DFT and HEOM approaches …”

“…Along with these applications, some novel phenomena have been discovered, such as the dynamical Coulomb blockade, the dynamical Kondo transition, and the quantum memristive effect . Recently, the HEOM‐QUICK program has been utilized in conjunction with density‐functional theory (DFT) methods, thus achieving first‐principles‐based simulation for the evolution of local quantum states in magnetic molecular impurities …”

Thermopower of few-electron quantum dots with Kondo correlations

“…It has been employed to investigate a wide range of equilibrium and nonequilibrium and static and dynamic properties of strongly correlated quantum impurity systems [49,52,53,57,58]. The numerical results of the HEOM approach are considered to be quantitatively accurate, as long as the results converge with respect to the truncation of the hierarchy.…”