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Montenegro-Pohlhammer N, Cárdenas-Jirón G, Calzado CJ. Voltage-induced modulation of the magnetic exchange in binuclear Fe(III) complex deposited on Au(111) surface. Dalton Trans 2024; 53:6264-6274. [PMID: 38506048 DOI: 10.1039/d4dt00580e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
We present a complete computational study devoted to the deposition of a magnetic binuclear complex on a metallic surface, aimed to obtain insight into the interaction of magnetically coupled complexes with their supporting substrates, as well as their response to external electrical stimuli applied through a surface-molecule-STM molecular junction-like architecture. Our results not only show that the deposition is favorable in two of the four studied orientations, but also, that the magnetic coupling is only slightly perturbed once the complex is adsorbed. We observe that the effects of the applied bias voltage on the magnetic coupling strongly depend on the molecule orientation with respect to the surface and the voltage polarity. Further analysis shows that this behavior is attributable to the stabilization/destabilization of the d-type singly occupied orbitals of the iron centers, reinforced by the strong local electric fields and induced charge densities only present in certain orientations of the deposited molecule and applied voltage polarity.
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Affiliation(s)
- Nicolás Montenegro-Pohlhammer
- Escuela de Ingeniería Civil, Facultad de Ingeniería, Ciencia y Tecnología, Universidad Bernardo O'Higgins, Santiago, Chile.
- Universidad Bernardo OHiggins, Centro Integrativo de Biología y Química Aplicada (CIBQA), General Gana 1702, Santiago, Chile
| | - Gloria Cárdenas-Jirón
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), Santiago, Chile
| | - Carmen J Calzado
- Departamento de Química Física. Universidad de Sevilla, c/Prof. García González, s/n 41012, Sevilla, Spain
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Senapati P, Parida P. Charge and spin thermoelectric transport in benzene-based molecular nano-junctions: a quantum many-body study. NANOSCALE 2024; 16:2574-2590. [PMID: 38224290 DOI: 10.1039/d3nr04714h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Within the Coulomb blockade regime, our study delves into the charge, spin, and thermoelectric transport characteristics of a benzene-based molecular nano-junction using the Pauli master equation and linear response theory. The charge- and spin-transport studies show strong negative differential conductance features in the current-voltage (I-V) characteristics for the ortho and meta connections of electrodes on either side. Contrarily, the para-connection displays Coulomb staircase behavior. By exploring spin current behavior in the presence of spin-polarized electrodes or an external Zeeman field, we establish a methodology that facilitates precise control over the specific spin flow. Various charge and spin thermoelectric transport coefficients have been studied with varying chemical potentials. We focus on spin-polarized conductance, the Seebeck coefficient, and the figure of merit. By adjusting electrode polarization or employing an external magnetic field, we achieve an impressive peak value for the spin thermoelectric figure of merit, approximately 4.10. This outcome underscores the strategic value of harnessing both spin-polarized electrodes and external magnetic fields within the domain of spin caloritronics.
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Affiliation(s)
- Parbati Senapati
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
| | - Prakash Parida
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
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Montenegro-Pohlhammer N, Kuppusamy SK, Cárdenas-Jirón G, Calzado CJ, Ruben M. Computational demonstration of isomer- and spin-state-dependent charge transport in molecular junctions composed of charge-neutral iron(II) spin-crossover complexes. Dalton Trans 2023; 52:1229-1240. [PMID: 36606462 DOI: 10.1039/d2dt02598a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemistry offers a multitude of opportunities towards harnessing functional molecular materials with application propensity. One emerging area of interest is molecular spintronics, in which charge and spin degrees of freedom have been used to achieve power-efficient device architectures. Herein, we show that, with the aid of state-of-the-art quantum chemical calculations on designer molecular junctions, the conductance and spin filtering capabilities are molecular structure-dependent. As inferred from the calculations, structural control over the transport can be achieved by changing the position of the thiomethyl (SMe) anchoring groups for Au(111) electrodes in a set of isomeric 2,2'-bipyridine-based metal coordinating ligand entities L1 and L2. The computational studies on heteroleptic iron(II) coordination complexes (1 and 2) composed of L1 and L2 reveal that switching the spin-state of the iron(II) centers, from the low-spin (LS) to high-spin (HS) state, by means of an external electric field stimulus, could, in theory, be performed. Such switching, known as spin-crossover (SCO), renders charge transport through single-molecule junctions of 1 and 2 spin-state-dependent, and the HS junctions are more conductive than the LS junctions for both complexes. Additionally, the LS and HS junctions based on complex 1 are more conductive than those featuring complex 2. Moreover, it is predicted that the spin filtering efficiency (SFE) of the HS junctions strongly depends on the bridging complex geometry, with 1 showing a voltage-dependent SFE, whereas 2 exhibits an SFE of practically 100% over all the studied voltage range. To be pragmatic towards applications, the ligands L1 and L2 and complex 1 have been successfully synthesized, and the spin-state switching propensity of 1 in the bulk state has been elucidated. The results shown in this study might lead to the synthesis and characterization of isomeric SCO complexes with tuneable spin-state switching and charge transport properties.
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Affiliation(s)
- Nicolás Montenegro-Pohlhammer
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile.
- Departamento de Química Física. Universidad de Sevilla, c/Profesor García González, s/n., 41012 Sevilla, Spain
| | - Senthil Kumar Kuppusamy
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| | - Gloria Cárdenas-Jirón
- Laboratory of Theoretical Chemistry, Faculty of Chemistry and Biology, University of Santiago de Chile (USACH), 9170022, Santiago, Chile.
| | - Carmen J Calzado
- Departamento de Química Física. Universidad de Sevilla, c/Profesor García González, s/n., 41012 Sevilla, Spain
| | - Mario Ruben
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Centre Européen de Sciences Quantiques (CESQ), Institut de Science et d'Ingénierie Supramoléculaire (ISIS), Université de Strasbourg, Strasbourg, France
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Single transition metal atoms anchored on a two-dimensional polyimide covalent-organic framework as single-atom catalysts for photocatalytic CO2 reduction: A first-principles study. CATAL COMMUN 2023. [DOI: 10.1016/j.catcom.2023.106604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Horniichuk OY, Ridier K, Zhang L, Zhang Y, Molnár G, Salmon L, Bousseksou A. High-Sensitivity Microthermometry Method Based on Vacuum-Deposited Thin Films Exhibiting Gradual Spin Crossover above Room Temperature. ACS APPLIED MATERIALS & INTERFACES 2022; 14:52140-52148. [PMID: 36374998 DOI: 10.1021/acsami.2c13834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We report on the fabrication, characterization, and microthermometry application of high-quality, nanometric thin films, with thicknesses in the range 20-200 nm, of the molecular spin-crossover complex [Fe(HB(1,2,3-triazol-1-yl)3)2]. The films were obtained by vacuum thermal evaporation and characterized by X-ray diffraction, UV spectrophotometry, and atomic force microscopy. The as-deposited films are dense and crystalline with a preferred [011] orientation of the monoclinic crystal lattice normal to the substrate surface. The films exhibit a gradual spin conversion centered at ca. 374 K spanning the 273-473 K temperature range, irrespective of their thickness. When deposited on a microelectronic device, these films can be used to enhance the UV-light thermoreflectance coefficient of reflective surfaces by more than an order of magnitude, allowing for high-sensitivity thermoreflectance thermal imaging.
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Affiliation(s)
- Oleksandr Ye Horniichuk
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
- Faculty of Chemistry, Taras Shevchenko National University of Kyiv, 12, Lva Tolstogo str., 01033, Kyiv, Ukraine
| | - Karl Ridier
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
| | - Lijun Zhang
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
| | - Yuteng Zhang
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
| | - Gábor Molnár
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
| | - Lionel Salmon
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
| | - Azzedine Bousseksou
- LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France
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