Perfect Spin Filtering in Homobimetallic Ni Complex with High Tolerance to Structural Changes

Abstract

In the theory of ligand fields, depending on the nature and field strength of the surrounding ligands, the central metal ion may exhibit different electronic configurations, low spin (LS) or high spin (HS). Realizing stable spin polarization is one of the main challenges in the field of molecular spintronic devices because of spin switching triggered by an external stimulus. Here, an asymmetric homobimetallic complex has been investigated using the nonequilibrium Green's function and spin density functional theory. Our calculations indicate that the homobimetallic complex can achieve negative differential resistance, rectification effect, and perfect spin filtering transport on the level of an individual molecule. Strikingly, when the molecule is stretched by 0.45 Å, the HS state is still the most stable because of the weak magnetic Ni−Ni interaction. Although its conductivity decreases by 30%, the efficiency of spin filtering remains 100%. These obtained theoretical findings suggest that the homobimetallic complexes hold great potential in molecular spintronics.

A theoretical study of laser-induced ultrafast spin dynamics in trigonal monopyramidal iron and nickel complexes

“…1,22 The exhibited large magnetic anisotropies and entropy changes also strongly indicate their great potential in high-density information storage, quantum computing and magnetic refrigeration. 23–26 One of the particular species is the mononuclear trigonal pyramidal transition metal (TM) complexes, for which the synthesis and characterization can be dated back to the 1990s. 27,28 With the TM center being spatially protected by the special ligand to avoid further ligand coordination, the fourfold coordinated configuration of this kind of structures also proved to be stable, and some of them were found to exhibit a high-spin configuration.…”

Negative Differential Resistance in Spin-Crossover Molecular Devices

“…In particular, negative differential resistance (NDR), characterized by a decreasing current with increasing bias in a certain bias voltage window, is one of the most attractive quantum tunneling phenomena. Stimulated by the promising electronic applications that the NDR effect can offer, the functional I – V behavior entailed in the NDR of single-molecule junctions has been extensively studied during the last two decades. − …”