Control of magnetic interactions between surface adatoms via orbital repopulation

Abstract

We propose a reversible mechanism for switching Heisenberg-type exchange interactions between deposited transition metal adatoms from ferromagnetic to antiferromagnetic. Using first-principles calculations, we show that this mechanism can be realized for cobalt atoms on the surface of black phosphorus by making use of electrically-controlled orbital repopulation, as recently demonstrated by scanning probe techniques [Nat. Commun. 9, 3904 (2018)]. We find that field-induced repopulation not only affects the spin state, but also causes considerable modification of exchange interaction between adatoms, including its sign. Our model analysis demonstrates that variable adatom-substrate hybridization is a key factor responsible for this modification. We perform quantum simulations of inelastic tunneling characteristics and discuss possible ways to verify the proposed mechanism experimentally.

Magnetism between magnetic adatoms on monolayer NbSe2

“…This implies that one can in principle manipulate the magnetic character of pair of atoms on top of NbSe 2 by moving them in-plane, without significant effects arising from the out-of-plane modifications. This seems to offer a better realization of the magnetic interaction control between adatoms by means of external bias voltage, recently proposed by Badrtdinov et al for phosphorene [70]. Furthermore, considering that NbSe 2 is metallic and that adatoms have a single spin configuration (without low and high spins), probing their magnetic interactions via inelastic electron tunneling spectroscopy seems much more feasible.…”

“…Other possible positions, as e.g. the bridge site positions between Nb and Se atoms, can be ignored based on previous studies on similar systems [18,19,41,69,70].…”

Magnetism between magnetic adatoms on monolayer NbSe$_2$

“…This implies that one can in principle manipulate the magnetic character of pair of atoms on top of NbSe 2 by moving them in-plane, without significant effects arising from the out-of-plane modifications. This seems to offer a better realization of the magnetic interaction control between adatoms by means of external bias voltage, recently proposed by Badrtdinov et al for phosphorene [69]. Furthermore, considering that NbSe 2 is metallic and that adatoms have a single spin configuration (without low and high spins), probing their magnetic interactions via inelastic electron tunneling spectroscopy (IETS) seems much more feasible.…”

“…Other possible positions, as e.g. the bridge site positions between Nb and Se atoms, can be ignored based on previous studies on similar systems [19,18,41,68,69]. We first performed a detailed analysis of the energetic landscape without including spin polarization.…”

Manipulations of Electronic and Spin States in Co-Quantum Dot/WS2 Heterostructure on a Metal-Dielectric Composite Substrate by Controlling Interfacial Carriers

“…Yang et al realized the precise tuning of the spin superposition states in Ti/MgO/Ag(001) by virtue of the local magnetic field from the magnetic STM tip . Although several works have discovered intriguing characteristics and magic modulation with an external field in vdW heterostructures, ,− manipulation of charge and spin properties utilizing the interfacial potential has barely been reported. The mechanism is also confusing and needs to be revealed at the quantum level.…”