Magnetic bistability: From microscopic to macroscopic understandings of hysteretic behavior using<i>ab initio</i>calculations

Képénékian, Mikaël; Guennic, Boris Le; Robert, Vincent

doi:10.1103/physrevb.79.094428

Cited by 59 publications

(81 citation statements)

References 30 publications

(28 reference statements)

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“…The energy gap then turns out to be different for the same molecule in different phases. 46,47 Unfortunately, this effect is always neglected by DFT calculations, which aim at assessing the performances of DFT by using experimental data.…”

Section: Electrostatic Contributions To the Total Energymentioning

confidence: 99%

Assessment of density functional theory for iron(II) molecules across the spin-crossover transition

Droghetti

Alfè

Sanvito

2012

The Journal of Chemical Physics

101

185

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Octahedral Fe2+ molecules are particularly interesting as they often exhibit a spin-crossover transition. In spite of the many efforts aimed at assessing the performances of density functional theory for such systems, an exchange-correlation functional able to account accurately for the energetic of the various possible spin-states has not been identified yet. Here, we critically discuss the issues related to the theoretical description of this class of molecules from first principles. 2+ , the failure is likely to be caused by the multiconfigurational character of the ground state wave-function and no suitable exchange and correlation functional has been identified.

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Section: Electrostatic Contributions To the Total Energymentioning

confidence: 99%

Assessment of density functional theory for iron(II) molecules across the spin-crossover transition

Droghetti

Alfè

Sanvito

2012

The Journal of Chemical Physics

101

185

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mentioning

confidence: 99%

“…G pol arises from the electrostatic potentials generated by the rest of the transiting sites and possibly the metallic surface at the position of (i) Fe ions (V LS , V HS ), and (ii) ligands (v LS , v HS ). 26,38 This contribution G pol to the Gibbs free energy reads :where ∆Q = Q HS − Q LS is the charge variation on the Fe center. δV HS and δV LS are the potential differences between metal and ligand positions in the HS and LS state, respectively.…”

mentioning

confidence: 99%

“…To that purpose, let us briefly recall the so-called polarization contribution. 38 In a mean-field scheme, the molar Gibbs free energy G of a mixture of spin transiting centers as a function of the HS molar fraction x reads A c c e p t e d m a n u s c r i p t where G ni = xG HS + (1 − x)G LS is the free energy of non-interacting sites. S mix is the entropy of mixing −R(x ln(x) + (1 − x) ln(1 − x)).…”

mentioning

confidence: 99%

“…Indeed, interactions between transiting units can be mediated by phonon coupling, electron-phonon coupling 36,37 and driven by the Madelung field modulation in the crystal. 26,38 In the following, we inspect changes in charge distribution resulting from dimensionality reduction and surface deposition. To that purpose, let us briefly recall the so-called polarization contribution.…”

mentioning

confidence: 99%

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Enhanced Cooperativity in Supported Spin-Crossover Metal–Organic Frameworks

Groizard

Papior

Guennic

et al. 2017

J. Phys. Chem. Lett.

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A c c e p t e d m a n u s c r i p t Molecular electronics originally proposed in the 1950s and reinvigorated by the founding proposition of Aviram and Ratner 1 has led to intense activity on the study of electronic transport through single molecules, supported by the advent of scanning tunneling microscopy (STM) and break junction setups. 2,3 More recently, molecules entered the field of spintronics, i.e. the control and manipulation of spins, 4 and gave birth to molecular spintronics, [5][6][7][8] where the working principle of the targeted devices relies on bistability. Molecular bistability has been best served by molecular magnetism with two distinct families: spin-crossover (SCO) compounds and single molecule magnets (SMM). 9,10 Whereas SMM display bistability at rather low temperatures, 9,10 higher temperature regimes are reached for SCO materials. 11 In order to bridge the gap between functional molecules and practical devices, one has to deposit the objects on a surface while retaining the bistability property. With respect to the intense activity in the field of adsorbed SMM, 8,[12][13][14][15] SCO supported compounds have received much less attention. It is only recently that supported examples have emerged, starting from 3-dimensional (3D) materials with thin-films grown on gold. 11,16,17 0D systems followed based on single SCO molecules, [18][19][20][21][22][23][24] or molecular junctions. 25 However, 2D monolayer organized networks exhibiting SCO behavior have not been reported so far. Not only should low-dimensional SCO patterns offer new insights into the spin transition phenomenon, but such organized networks may also offer the opportunity to control the intermolecular interactions dictating the collective behavior of transiting centers (a.k.a. cooperativity). 26 With this goal in mind, a promising route might come from the use of self-assembled metalorganic framework (MOF). 27 Indeed, magnetic couplings 28 were reported in several 2D MOF based on 3d ions such as Fe, 29,30 Ni, 31 Mn 32,33 or Cu. 34 Recently, Umbach et al. have investigated a Au(111)-supported MOF based on Fe(II) ions and 2,4,6-tris(4-pyridyl)-1,3,5-triazine (T4PT) ligand. 30 Interestingly, in addition to the observation of a weakly ferromagnetic behaviour, the speculated structure of the system consists in FeN 6 units, an archetype arrangement of SCO systems. 35 In this letter, we use a model based on Fe(II) transiting unit to investigate the effect of dimensionality reduction and surface deposition. Our thermodynamic model shows that a metallic A c c e p t e d m a n u s c r i p t substrate is likely to enhance cooperativity by an order of magnitude. In the light of these findings, we then perform calculations based on density functional theory (DFT) to establish the structure of the synthetic Fe-T4PT MOF supported on a Au(111) surface. 30 We show that the most stable structure consists of FeN 3 Au 3 units rather than on the expected FeN 6 building blocks. Beyond the interpretation of experimental results, a chemical mo...

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Spin‐Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films

et al. 2021

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Molecular spintronics seeks to use single or few molecules as functional building blocks for spintronic applications, directly relying on molecular properties or properties of interfaces between molecules and inorganic electrodes. Spin‐crossover molecules (SCMs) are one of the most promising classes of candidates for molecular spintronics due to their bistability deriving from the existence of two spin states that can be reversibly switched by temperature, light, electric fields, etc. Building devices based on single or few molecules would entail connecting the molecule(s) with solid surfaces and understanding the fundamental behavior of the resulting assemblies. Herein, the investigations of SCMs on solid surfaces, ranging from isolated single molecules (submonolayers) to ultrathin films (mainly in the sub‐10 nm range) are summarized. The achievements, challenges and prospects in this field are highlighted.

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Magnetic bistability: From microscopic to macroscopic understandings of hysteretic behavior usingab initiocalculations

Cited by 59 publications

References 30 publications

Assessment of density functional theory for iron(II) molecules across the spin-crossover transition

Assessment of density functional theory for iron(II) molecules across the spin-crossover transition

Enhanced Cooperativity in Supported Spin-Crossover Metal–Organic Frameworks

Spin‐Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films

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