Magnetic and transport properties of Fe₄single-molecule magnets: a theoretical insight

Abstract

Here, methods of density functional theory (DFT) were employed to study the magnetic and transport properties of a star-shaped single-molecule magnet FeS = 5 complex deposited on a gold surface. The study devoted to the magnetic properties focused on changes in the exchange coupling constants and magnetic anisotropy (zero-field splitting parameters) of the isolated and deposited molecules. Molecule-surface interactions induced significant changes in the antiferromagnetic exchange coupling constants because these depend closely on the geometry of the metal complex. Meanwhile, the magnetic anisotropy remained almost constant. Transport properties were analysed using two different approaches. First, we studied the change in magnetic anisotropy by reducing and oxidizing the Fe complex as in a Coulomb blockade mechanism. Then we studied the coherent tunnelling using DFT methods combined with Green functions. Spin filter behaviour was found because of the different numbers of alpha and beta electrons, due to the S = 5 ground state.

Engineering Chemisorption of Fe4 Single‐Molecule Magnets on Gold

“…[ 23 ] Solution chemistry was used to capture individual Fe 4 molecules in gated metal nanogaps and study the interplay between electron transport and magnetic properties. [ 24–27 ] In an alternative approach to single‐molecule addressing, Fe 4 complexes were deposited on atomically flat surfaces suitable for scanning probe studies, including Au(111), [ 9,10,28–32 ] Cu(100), [ 32 ] Cu 2 N/Cu(100), [ 32,33 ] BN/Rh(111), [ 34 ] graphene/Ir(111), [ 35,36 ] and Pb(111). [ 37 ] In particular, the investigation of sulfur‐functionalized Fe 4 derivatives chemisorbed on Au(111) surface by a wet chemistry approach marked a turning point in the field, as it provided the first sound demonstration that molecule‐surface interactions may not critically affect SMM properties.…”

“…[23] Solution chemistry was used to capture individual Fe 4 molecules in gated metal nanogaps and study the interplay between electron transport and magnetic properties. [24][25][26][27] In an alternative approach to single-molecule addressing, Fe 4 complexes were deposited on atomically flat surfaces suitable for scanning probe studies, including Au(111), [9,10,[28][29][30][31][32] Cu(100), [32] Cu 2 N/Cu(100), [32,33] BN/Rh(111), [34] A. Juhin, M.-A. Arrio, W. graphene/Ir(111), [35,36] and Pb(111).…”

Transport property of ligand-driven light-induced spin-change Fe-based spin crossover complexes

“…1,2 The transport behavior of Fe-based LD-LISC SCO complexes is limited so far, mostly because it is very challenging due to difficulties associated with the controllable anchoring contact in devices. 22,23 In this work, we explore the transport properties of Fe(stpy) 4 (NCS) 2 SCO complexes with the trans and cis congurations sandwiched between two Au nanoelectrodes by performing extensive density functional theory calculations combined with nonequilibrium Green's function method. As for the trans conguration, the current through the molecular junction with the HS state is signicantly larger than that of the LS state, which indicates that this Fe-based SCO complex with the trans conguration could act as a molecular switch when the spin transition is triggered by external stimuli.…”