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Ghifari N, Bennacer R, Chahboun A, El Abed AI. Hierarchical Self-Assembly of Dipolar ZnO Nanoparticles and Microdroplets. MICROMACHINES 2022; 13:1522. [PMID: 36144145 PMCID: PMC9502180 DOI: 10.3390/mi13091522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
In this work, we investigated the orientation and the polarization of ZnO nanoparticles, which serve as building blocks of highly monodisperse microspheres, using a droplet microfluidic-assisted synthesis method. We observe, for the first time, a square lattice organization of liquid microdroplets, in a steady state, at the oil/water interface. Such square organization reveals clearly a dipolar organization of ZnO nanoparticles at the surfaces of droplets at the early stage of ZnO nanocrystal aggregation and microsphere formation. We discuss different models of organization of ZnO nanoparticles and show that the well-known tip-streaming effect in droplets in microfluidics explains the reason for the obtained dipolar droplets. The square organization is illustrated and explained.
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Affiliation(s)
- Najla Ghifari
- Laboratoire Lumière Matière et Interfaces (LUMIN), UMR 9024, Ecole Normale Supérieure Paris Saclay, CentraleSupélec, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190 Gif-sur-Yvette, France
| | - Rachid Bennacer
- ENS Paris-Saclay, CNRS, LMPS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Adil Chahboun
- Laboratoire des Couches Minces et Nanomatériaux (CMN), FST Tanger, Université Abdelmalek Essaadi, BP 416, Tangier 90000, Morocco
| | - Abdel I. El Abed
- Laboratoire Lumière Matière et Interfaces (LUMIN), UMR 9024, Ecole Normale Supérieure Paris Saclay, CentraleSupélec, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190 Gif-sur-Yvette, France
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Bernardini F, Boeri L, Floris A, Franchini C, Profeta G, Sanna A. Special issue on novel superconducting and magnetic materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:040401. [PMID: 31600741 DOI: 10.1088/1361-648x/ab4cbe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Fabio Bernardini
- CNR-IOM-Cagliari and Dipartimento di Fisica, Universit di Cagliari, 09042 Monserrato, Italy. Dipartimento di Fisica, Sapienza Universit di Roma, 00185 Roma, Italy. School of Mathematics and Physics, University of Lincoln, Brayford Pool, LN6 7TS, Lincoln, United Kingdom. University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna, Austria. Dipartimento di Fisica e Astronomia, Universit di Bologna, I-40127 Bologna, Italy. CNR-SPIN and Dipartimento di Fisica, Universit degli Studi di L'Aquila, Via Vetoio 10, I-67100 L'Aquila, Italy. Max Planck Institut fr Microstrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Liu J, Pantelides ST. Mechanisms of Pyroelectricity in Three- and Two-Dimensional Materials. PHYSICAL REVIEW LETTERS 2018; 120:207602. [PMID: 29864359 DOI: 10.1103/physrevlett.120.207602] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Indexed: 06/08/2023]
Abstract
Pyroelectricity is a very promising phenomenon in three- and two-dimensional materials, but first-principles calculations have not so far been used to elucidate the underlying mechanisms. Here we report density-functional theory (DFT) calculations based on the Born-Szigeti theory of pyroelectricity, by combining fundamental thermodynamics and the modern theory of polarization. We find satisfactory agreement with experimental data in the case of bulk benchmark materials, showing that the so-called electron-phonon renormalization, whose contribution has been traditionally viewed as negligible, is important. We predict out-of-plane pyroelectricity in the recently synthesized Janus MoSSe monolayer and in-plane pyroelectricity in the group-IV monochalcogenide GeS monolayer. It is notable that the so-called secondary pyroelectricity is found to be dominant in GeS monolayer. The present work opens a theoretical route to study the pyroelectric effect using DFT and provides a valuable tool in the search for new candidates for pyroelectric applications.
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Affiliation(s)
- Jian Liu
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Sokrates T Pantelides
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tenessee 37235, USA
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Yang W, Zhang B, Zhang Q, Wang L, Song B, Ding Y, Wong CP. Adjusting the band structure and defects of ZnO quantum dots via tin doping. RSC Adv 2017. [DOI: 10.1039/c6ra25940e] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The structures and band structures of Sn doped ZnO were investigated by density functional theory as well as experiment.
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Affiliation(s)
- Weimin Yang
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 210009
- China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites
| | - Bing Zhang
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 210009
- China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites
| | - Qitu Zhang
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 210009
- China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites
| | - Lixi Wang
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 210009
- China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites
| | - Bo Song
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - Yong Ding
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
| | - C. P. Wong
- School of Materials Science and Engineering
- Georgia Institute of Technology
- Atlanta
- USA
- Faculty of Engineering
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Bendavid LI, Carter EA. Status in Calculating Electronic Excited States in Transition Metal Oxides from First Principles. Top Curr Chem (Cham) 2014; 347:47-98. [DOI: 10.1007/128_2013_503] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Morales-Rodríguez HJ, Espinosa-Magaña F. Experimental and theoretical determination of the low-loss electron energy loss spectroscopy of nanostructured ZnO. Micron 2011; 43:177-82. [PMID: 21813282 DOI: 10.1016/j.micron.2011.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/10/2011] [Accepted: 07/10/2011] [Indexed: 10/17/2022]
Abstract
The dielectric properties of nanostructured wurtzite-type ZnO are studied by analyzing the low-loss region of the electron energy loss spectroscopy (EELS) in a transmission electron microscope. Characteristic peaks at about 12 and 32 eV in the imaginary part of the dielectric function shift to lower energies as particle size decreases. A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA), GGA+U and modified Becke-Johnson (mBJ) is presented. The origins of interband transitions are identified in the electronic band structure by calculating the partial imaginary part of the dielectric function and the partial density of states of Zn and O.
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Affiliation(s)
- H J Morales-Rodríguez
- Centro de Investigación en Materiales Avanzados, S.C., Laboratorio Nacional de Nanotecnología Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Chihuahua, Mexico
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Abstract
AbstractWe have investigated the electronic structures of p- or n-type doped ZnO based on ab initio electronic band structure calculations in order to control valence states in ZnO for the fabrication of low-resistivity p-type ZnO. We find unipolarity in ZnO; p-type doping using Li or N increases the Madelung energy while n-type doping using Al, Ga, In or F species decreases the Madelung energy. We have proposed materials design: codoping using N acceptors and reactive codopants, Al or Ga, enhances electric properties in p-type codoped ZnO. It has been already verified by experiments using the N acceptors and Ga reactive donor codopants. We find a very weak repulsive interaction between Li acceptors and the delocalization of the Li-impurity states for Lidoped ZnO, in contrast with the case of N-doped ZnO. On the other hand, we find the compensation mechanism by the formation of 0 vacancy in the vicinity of the Li-acceptor sites. We propose a group VII element, F species, as a promising candidate for use of the reactive codopant as for Li-doped ZnO in order to realize low-resistivity p-type ZnO.
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Resta R. Electrical polarization and orbital magnetization: the modern theories. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:123201. [PMID: 21389484 DOI: 10.1088/0953-8984/22/12/123201] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Macroscopic polarization P and magnetization M are the most fundamental concepts in any phenomenological description of condensed media. They are intensive vector quantities that intuitively carry the meaning of dipole per unit volume. But for many years both P and the orbital term in M evaded even a precise microscopic definition, and severely challenged quantum-mechanical calculations. If one reasons in terms of a finite sample, the electric (magnetic) dipole is affected in an extensive way by charges (currents) at the sample boundary, due to the presence of the unbounded position operator in the dipole definitions. Therefore P and the orbital term in M--phenomenologically known as bulk properties--apparently behave as surface properties; only spin magnetization is problemless. The field has undergone a genuine revolution since the early 1990s. Contrary to a widespread incorrect belief, P has nothing to do with the periodic charge distribution of the polarized crystal: the former is essentially a property of the phase of the electronic wavefunction, while the latter is a property of its modulus. Analogously, the orbital term in M has nothing to do with the periodic current distribution in the magnetized crystal. The modern theory of polarization, based on a Berry phase, started in the early 1990s and is now implemented in most first-principle electronic structure codes. The analogous theory for orbital magnetization started in 2005 and is partly work in progress. In the electrical case, calculations have concerned various phenomena (ferroelectricity, piezoelectricity, and lattice dynamics) in several materials, and are in spectacular agreement with experiments; they have provided thorough understanding of the behaviour of ferroelectric and piezoelectric materials. In the magnetic case the very first calculations are appearing at the time of writing (2010). Here I review both theories on a uniform ground in a density functional theory (DFT) framework, pointing out analogies and differences. Both theories are deeply rooted in geometrical concepts, elucidated in this work. The main formulae for crystalline systems express P and M in terms of Brillouin-zone integrals, discretized for numerical implementation. I also provide the corresponding formulae for disordered systems in a single k-point supercell framework. In the case of P the single-point formula has been widely used in the Car-Parrinello community to evaluate IR spectra.
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Affiliation(s)
- Raffaele Resta
- Dipartimento di Fisica, Università di Trieste, Strada Costiera 11, I-34014 Trieste, Italy
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Labat F, Ciofini I, Adamo C. Modeling ZnO phases using a periodic approach: From bulk to surface and beyond. J Chem Phys 2009; 131:044708. [DOI: 10.1063/1.3179752] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Mitani M, Takano Y, Yoshioka Y, Yamaguchi K. Density functional study of intramolecular ferromagnetic interaction through m-phenylene coupling unit. III. Possibility of high-spin polymer. J Chem Phys 1999. [DOI: 10.1063/1.479317] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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