Origin of Asymmetric Splitting of Kondo Peak in Spin-Polarized Scanning Tunneling Spectroscopy: Insights from First-Principles-Based Simulations

Abstract

The spin-polarized scanning tunneling microscope (SP-STM) has served as a versatile tool for probing and manipulating the spintronic properties of atomic and molecular devices with high precision. The interplay between the local spin state and its surrounding magnetic environment significantly affects the transport behavior of the device. Particularly, in the contact regime, the strong hybridization between the SP-STM tip and the magnetic atom or molecule could give rise to unconventional Kondo resonance signatures in the differential conductance (dI/dV) spectra. This poses challenges for the simulation of a realistic tip control process. By combining the density functional theory and the hierarchical equations of motion methods, we achieve first-principles-based simulation of the control of a Ni-tip/Co/Cu(100) junction in both the tunneling and contact regimes. The calculated dI/dV spectra reproduce faithfully the experimental data. A cotunneling mechanism is proposed to elucidate the physical origin of the observed unconventional Kondo signatures.

Tweezer-like magnetic tip control of the local spin state in the FeOEP/Pb(111) adsorption system: a preliminary exploration based on first-principles calculations

“…31,66,67 Δ i ασ is extracted from the Kohn–Sham Green function with or without the coupled substrate (or tip). 30 The details are described in section S4 of the ESI †…”

“…[26][27][28][29] Recently, Zhuang et al used the DFT + HEOM method to reproduce the experimental phenomena reported by Choi's group 17 and proposed a co-tunnelling mechanism to explain the physical origin of asymmetric Kondo splitting. 30 Using the combined DFT + CASSCF + HEOM method, our group accurately simulated the spin state control induced by the STM tip in the FeOEP/Pb(111) adsorption system. 31 However, due to the complex interactions between the molecule and its environment, theoretical simulations of magnetictip-induced anomalous quantum behaviour in molecule/ surface adsorption systems remain limited.…”

Quantum mechanics of open systems: Dissipaton theories

“…52 These studies include Kondo transport, magnetic anisotropy manipulation, spin-polarized scanning tunneling spectroscopy and so on. [112][113][114][115] Furthermore, there would be a so-called dissipaton embedded quantum master equation formalism, with system-plus-dissipatons being all incorporated into a single master equation. This provides an alternative formalism for quantum simulations in both bosonic and fermionic scenarios.…”

Unveiling the Decisive Factor for the Sharp Transition in the Scanning Tunneling Spectroscopy of a Single Nickelocene Molecule

“…For the sake of numerical convenience, a Lorentzian function of the form normalΓ α ν ( ω ) = normalΓ α ν W α 2 false( ω − normalΩ α false) 2 + W α 2 is adopted, where Γ αν is the effective hybridization strength between the νth d orbital on the Ni ion and the s bands in the αth reservoir and Ω α and W α are the band center and bandwidth of the αth reservoir, respectively. The involved energetic parameters (ϵ ν , U ν , Γ αν , W α , and Ω α ) are extracted from the DFT calculations ,,− (see section S3 of the Supporting Information for details). In particular, the magnitudes of s–d hybridization strength Γ αν are obtained by analyzing the Kohn–Sham Green’s functions. , The parametrized AIM is then solved by using the Fermionic HEOM method, which is capable of addressing the impurity–reservoir hybridization, electron transport, multielectron cotunneling, and strong correlation effect in a nonperturbative manner. ,, …”

“…The involved energetic parameters (ϵ ν , U ν , Γ αν , W α , and Ω α ) are extracted from the DFT calculations ,,− (see section S3 of the Supporting Information for details). In particular, the magnitudes of s–d hybridization strength Γ αν are obtained by analyzing the Kohn–Sham Green’s functions. , The parametrized AIM is then solved by using the Fermionic HEOM method, which is capable of addressing the impurity–reservoir hybridization, electron transport, multielectron cotunneling, and strong correlation effect in a nonperturbative manner. ,, …”