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Burnett LA, Clay MP, Vohra YK, Chen CC. First-principles calculation of Hubbard Ufor Terbium metal under high pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425602. [PMID: 39008992 DOI: 10.1088/1361-648x/ad6387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/15/2024] [Indexed: 07/17/2024]
Abstract
Using density functional theory (DFT) and linear response approaches, we compute the on-site Hubbard interactionUof elemental Terbium (Tb) metal in the pressure range ∼ 0-65 GPa. The resulting first-principlesUvalues with experimental crystal structures enable us to examine the magnetic properties of Tb using a DFT+U method. The lowest-energy magnetic states in our calculations for different high-pressure Tb phases-including hcp,α-Sm, and dhcp-are found to be compatible with the corresponding magnetic ordering vectors reported in experiments. The result shows that the inclusion of HubbardUsubstantially improves the accuracy and efficiency in modeling correlated rare-earth materials. Our study also provides the necessaryUinformation for other quantum many-body techniques to study Tb under extreme pressure conditions.
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Affiliation(s)
- Logan A Burnett
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America
| | - Matthew P Clay
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America
| | - Yogesh K Vohra
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America
| | - Cheng-Chien Chen
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America
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2
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Domański M, van Leusen J, Metzelaars M, Kögerler P, Grochala W. Ag(II) as Spin Super-Polarizer in Molecular Spin Clusters. J Phys Chem A 2022; 126:9618-9626. [PMID: 36521028 PMCID: PMC9806831 DOI: 10.1021/acs.jpca.2c06032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using quantum mechanical calculations, we examine magnetic (super)exchange interactions in hypothetical, chemically reasonable molecular coordination clusters containing fluoride-bridged late transition metals or selected lanthanides, as well as Ag(II). By referencing to analogous species comprising closed-shell Cd(II), we provide theoretical evidence that the presence of Ag(II) may modify the magnetic properties of such systems (including metal-metal superexchange) to a surprising degree, specifically both coupling sign and strength may markedly change. Remarkably, this happens in spite of the fact that the fluoride ligand is the least susceptible to spin polarization among all monoatomic ligands known in chemistry. In an extreme case of an oxo-bridged Ni(II)2 complex, the presence of Ag(II) leads to a nearly 17-fold increase of magnetic superexchange and switching from antiferro (AFM)- to ferromagnetic (FM) coupling. Ag(II)─with one hole in its d shell that may be shared with or transferred to ligands─effectively acts as spin super-polarizer, and this feature could be exploited in spintronics and diverse molecular devices.
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Affiliation(s)
- Mateusz Domański
- Center
of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02089Warsaw, Poland
| | - Jan van Leusen
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany
| | - Marvin Metzelaars
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany
| | - Paul Kögerler
- Institut
für Anorganische Chemie, RWTH Aachen
University, 52056Aachen, Germany,
| | - Wojciech Grochala
- Center
of New Technologies, University of Warsaw, Zwirki i Wigury 93, 02089Warsaw, Poland,
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Apostolova I, Apostolov A, Wesselinowa J. Band Gap Tuning in Transition Metal and Rare-Earth-Ion-Doped TiO 2, CeO 2, and SnO 2 Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:145. [PMID: 36616055 PMCID: PMC9824300 DOI: 10.3390/nano13010145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/22/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
The energy gap Eg between the valence and conduction bands is a key characteristic of semiconductors. Semiconductors, such as TiO2, SnO2, and CeO2 have a relatively wide band gap Eg that only allows the material to absorb UV light. Using the s-d microscopic model and the Green's function method, we have shown two possibilities to reduce the band-gap energy Eg-reducing the NP size and/or ion doping with transition metals (Co, Fe, Mn, and Cu) or rare earth (Sm, Tb, and Er) ions. Different strains appear that lead to changes in the exchange-interaction constants, and thus to a decrease in Eg. Moreover, the importance of the s-d interaction, which causes room-temperature ferromagnetism and band-gap energy tuning in dilute magnetic semiconductors, is shown. We tried to clarify some discrepancies in the experimental data.
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Affiliation(s)
| | - Angel Apostolov
- University of Architecture, Civil Engineering and Geodesy, Hristo Smirnenski Blvd. 1, 1046 Sofia, Bulgaria
| | - Julia Wesselinowa
- Sofia University “St. Kliment Ohridski”, J. Bouchier Blvd. 5, 1164 Sofia, Bulgaria
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Bhattacharyya S, Bandyopadhyay D, Mukund S, Sen P, Nakhate SG. Ionization Energies and Ground-State Structures of Neutral La n ( n = 2-14) Clusters: A Combined Experimental and Theoretical Investigation. J Phys Chem A 2022; 126:3135-3144. [PMID: 35580328 DOI: 10.1021/acs.jpca.2c00967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neutral lanthanum clusters are studied by photoionization time-of-flight mass spectroscopy, laser threshold photoionization spectroscopy, and density functional theory (DFT). Mass abundance spectra (MS) registered at multiple photoionization wavelengths in the range of 195-230 nm by single photon ionization reveal the production of all sizes, Lan (n ≥ 50), in good abundance, nullifying previously predicted low abundances for certain sizes in the 3-14 size range. Also, the MS do not reveal the extraordinary stability of any specific size, as one would expect, from previous theoretical predictions of 7- and 13-atom clusters as magic. Ionization energies (IEs) are measured for Lan (n = 2-14) clusters. DFT has been used to determine the stable geometric isomers for 2- to 10-atom clusters and to calculate their IEs. The theoretical IEs of 2-7 atom clusters are in decent agreement with their experimental values; however, the theoretical IEs are somewhat lower by ∼0.4 eV for n ≥ 8 than their experimental IEs.
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Affiliation(s)
- Soumen Bhattacharyya
- Infrared Laser Spectroscopy Section, Physics Group, Bhabha Atomic Research Centre, Mumbai 400 085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, India
| | - Debashis Bandyopadhyay
- Physics Department, Birla Institute of Technology and Science, Pilani 333031, Rajasthan, India
| | - Sheo Mukund
- Infrared Laser Spectroscopy Section, Physics Group, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Prasenjit Sen
- Harish-Chandra Research Institute, a CI of Homi Bhabha National Institute, Prayagraj, Allahabad, Uttar Pradesh 211019, India
| | - Sanjay G Nakhate
- Infrared Laser Spectroscopy Section, Physics Group, Bhabha Atomic Research Centre, Mumbai 400 085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094, India
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Li X, Chen Y, Basnet P, Luo J, Wang H. Probing the properties of size dependence and correlation for tantalum clusters: geometry, stability, vibrational spectra, magnetism, and electronic structure. RSC Adv 2019; 9:1015-1028. [PMID: 35517637 PMCID: PMC9059546 DOI: 10.1039/c8ra09240k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 12/20/2018] [Indexed: 11/30/2022] Open
Abstract
A comprehensive investigation on the equilibrium geometry, relative stability, vibrational spectra, and magnetic and electronic properties of neutral tantalum clusters (Tan, n = 2–17) was performed using density functional theory (DFT). We perform a study of the size dependence and correlations among those descriptors of parameters, and showed these could provide a novel way to confirm and predict experimental results. Some new isomer configurations that have never been reported before for tantalum clusters were found. The growth behaviors revealed that a compact geometrical growth route is preferred and develops a body-centered-cubic (BCC) structure with the cluster size increasing. The perfectly fitted functional curve, strong linear evolution, and obvious odd–even oscillation behavior proved their corresponding properties depended on the cluster size. Multiple demonstrations of the magic number were confirmed through the correlated relationships with the relative stability, including the second difference in energy, maximum hardness, and minimum polarizability. An inverse evolution trend between the energy gap and electric dipole moment and strong linear correlation between ionization potentials and polarizability indicated the strong correlation between the magnetic and electronic properties. Vibrational spectroscopy as a fingerprint was used to distinguish the ground state among the competitive geometrical isomers close in energy. The charge density difference isosurface, density of states, and molecular orbitals of selected representative clusters were analyzed to investigate the difference and evolutional trend of the relative stability and electronic structure. In addition, we first calculated the ionization potential and magnetic moment and compared these with the current available experimental data for tantalum clusters. A comprehensive investigation on the equilibrium geometry, relative stability, vibrational spectra, and magnetic and electronic properties of neutral tantalum clusters (Tan, n = 2–17) was performed using density functional theory (DFT).![]()
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Affiliation(s)
- Xibo Li
- Science and Technology on Plasma Physics Laboratory
- Laser Fusion Research Center
- China Academy of Engineering Physics
- Mianyang
- China
| | - Yuqi Chen
- School of Physical Science and Technology
- Southwest Jiaotong University
- Chengdu
- China
| | - Pradip Basnet
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - Jiangshan Luo
- Science and Technology on Plasma Physics Laboratory
- Laser Fusion Research Center
- China Academy of Engineering Physics
- Mianyang
- China
| | - Hongyan Wang
- School of Physical Science and Technology
- Southwest Jiaotong University
- Chengdu
- China
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Affiliation(s)
- Bayileyegn A. Abate
- Science of Advanced Materials and ‡Department of Physics, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
| | - Rajendra P. Joshi
- Science of Advanced Materials and ‡Department of Physics, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
| | - Juan E. Peralta
- Science of Advanced Materials and ‡Department of Physics, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
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Scheerder JE, Picot T, Reckinger N, Sneyder T, Zharinov VS, Colomer JF, Janssens E, Van de Vondel J. Decorating graphene with size-selected few-atom clusters: a novel approach to investigate graphene-adparticle interactions. NANOSCALE 2017; 9:10494-10501. [PMID: 28703819 DOI: 10.1039/c7nr02217d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We investigated the interaction between size-selected Au2 and Au3 clusters and graphene. Hereto preformed clusters are deposited on graphene field-effect transistors, a novel approach which offers a high control over the number of atoms per cluster, the deposition energy and the deposited density. The induced p-doping and charge carrier scattering indicate that a major part of the deposited clusters remains on the graphene flake as either individual or sub-nm coalesced entities. This is independently confirmed by scanning electron microscopy on the same devices after current annealing. Our novel approach provides perspectives for the electronic sensing of metallic clusters down to their atom-by-atom size-specific properties, and exploiting the tunability of clusters for tailoring desired properties in graphene.
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Affiliation(s)
- Jeroen E Scheerder
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
| | - Thomas Picot
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
| | - Nicolas Reckinger
- Research Group on Carbon Nanostructures (CARBONNAGe), University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Tomas Sneyder
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
| | - Vyacheslav S Zharinov
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
| | - Jean-François Colomer
- Research Group on Carbon Nanostructures (CARBONNAGe), University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Ewald Janssens
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
| | - Joris Van de Vondel
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200 D, box 2414, BE-3001 Leuven, Belgium.
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Mendive-Tapia E, Staunton JB. Theory of Magnetic Ordering in the Heavy Rare Earths: Ab Initio Electronic Origin of Pair- and Four-Spin Interactions. PHYSICAL REVIEW LETTERS 2017; 118:197202. [PMID: 28548504 DOI: 10.1103/physrevlett.118.197202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Indexed: 06/07/2023]
Abstract
We describe a disordered local moment theory for long-period magnetic phases and investigate the temperature and magnetic field dependence of the magnetic states in the heavy rare earth elements (HREs), namely, paramagnetic, conical and helical antiferromagnetic (HAFM), fan, and ferromagnetic (FM) states. We obtain a generic HRE magnetic phase diagram which is consequent on the response of the common HRE valence electronic structure to f-electron magnetic moment ordering. The theory directly links the first-order HAFM-FM transition to the loss of Fermi surface nesting, induced by this magnetic ordering, as well as provides a template for analyzing the other phases and exposing where f-electron correlation effects are particularly intricate. Gadolinium, for a range of hexagonal, close-packed lattice constants c and a, is the prototype, described ab initio, and applications to other HREs are made straightforwardly by scaling the effective pair and quartic local moment interactions that emerge naturally from the theory with de Gennes factors and choosing appropriate lanthanide-contracted c and a values.
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Affiliation(s)
| | - Julie B Staunton
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
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