1
|
Huang C. Exchange-correlation potential built on the derivative discontinuity of electron density. J Chem Phys 2024; 161:084103. [PMID: 39171704 DOI: 10.1063/5.0223499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 08/07/2024] [Indexed: 08/23/2024] Open
Abstract
Electronic structures are fully determined by the exchange-correlation (XC) potential. In this work, we develop a new method to construct reliable XC potentials by properly mixing the exact exchange and the local density approximation potentials in real space. The spatially dependent mixing parameter is derived based on the derivative discontinuity of electron density and is first-principle. We derived the equations for solving the mixing parameter and proposed an approximation to simplify these equations. Based on this approximation, this new method gives reasonable predictions for the ionization energies, fundamental gaps, and singlet-triplet energy differences for various molecular systems. The impact of the approximation on the constructed XC potentials is examined, and it is found that the quality of the XC potentials can be further improved by removing the approximation. This work demonstrates that the derivative discontinuity of electron density is a promising constraint for constructing high-quality XC potentials.
Collapse
Affiliation(s)
- Chen Huang
- Department of Scientific Computing, Materials Science and Engineering Program, and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA
| |
Collapse
|
2
|
Shavez M, Mahapatra S. Effect of heterocyclic and non-heterocyclic units on FDT-based hole transport materials for efficient perovskite solar cells: a DFT study. Phys Chem Chem Phys 2024; 26:22378-22387. [PMID: 39139134 DOI: 10.1039/d4cp01317d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
The development of a new structure is one of the important approaches for the advancement of efficient hole-transporting materials (HTMs). In this work, novel and efficient HTMs are designed based on the experimentally reported fluorene-dithiophene (FDT) system which shows the effect of four different units phenyl, pyridine, thiane, and oxane in the FDT unit. The structural, optoelectronic, and charge transport properties of the newly developed HTMs are probed using density functional theory (DFT) and time-dependent DFT (TD-DFT) methodologies. The calculated highest occupied molecular orbital (HOMO) energies for all HTMs are higher compared to the valence band energy level of the perovskite which exhibits outstanding hole extraction ability of all HTMs at the charge buffer interface. In addition, the designed HTMs have red-shifted absorption spectra compared to FDT. The computed hole mobilities of newly designed HTMs are faster compared to that of FDT. Moreover, newly tailored HTMs demonstrate improved solubility. The results indicate that a one thiane and one phenyl unit-based system among all materials is the most suitable for HTM design.
Collapse
Affiliation(s)
- Mohd Shavez
- School of Chemistry, University of Hyderabad, Hyderabad, 500046, India.
| | - S Mahapatra
- School of Chemistry, University of Hyderabad, Hyderabad, 500046, India.
| |
Collapse
|
3
|
da Silva Barboza E, Cruz KLM, Ferreira RS, Dias AC, Lima EN, da Costa DR, Pereira TAS. Stability and Optoelectronic Properties of Two-Dimensional Gallium Phosphide. ACS OMEGA 2024; 9:35666-35675. [PMID: 39184476 PMCID: PMC11339990 DOI: 10.1021/acsomega.4c03861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/24/2024] [Accepted: 07/30/2024] [Indexed: 08/27/2024]
Abstract
Using first-principles calculations, density functional theory, and the tight-binding method, we investigate the optoelectronic properties of two-dimensional gallium phosphide (2D GaP). Our investigation covers electronic properties, such as band structure and electronic band gap, and optical properties, including absorption spectra, refractive index, and reflectivity, considering excitonic effects. Additionally, structural aspects such as stability, elastic properties, and Raman and infrared spectra are also analyzed. This comprehensive study brings up valuable insights into 2D GaP physics, evincing the key features that make it a potential material for optoelectronic applications, such as photodetectors and solar cells.
Collapse
Affiliation(s)
| | - Kessia L. M. Cruz
- Instituto
de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, Mato Grosso, Brazil
| | - Ramon S. Ferreira
- Instituto
de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, Mato Grosso, Brazil
- Departamento
de Física, Universidade Federal do
Piauí, 64049-550 Teresina, Piauí, Brazil
- National
Institute of Science and Technology on Materials Informatics, 13083-886 Campinas, Brazil
| | - Alexandre C. Dias
- Institute
of Physics and International Center of Physics, University of Brasília, Brasília 70919-970, Distrito Federal, Brazil
| | - Erika N. Lima
- Instituto
de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, Mato Grosso, Brazil
| | - Diego R. da Costa
- Departamento
de Física, Universidade Federal do
Ceará, Campus do Pici, 60455-900 Fortaleza, Ceará, Brazil
- Department
of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Teldo A. S. Pereira
- Instituto
de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, Mato Grosso, Brazil
- National
Institute of Science and Technology on Materials Informatics, 13083-886 Campinas, Brazil
| |
Collapse
|
4
|
Mahmoudi Gahrouei M, Vlastos N, D’Souza R, Odogwu EC, de Sousa Oliveira L. Benchmark Investigation of SCC-DFTB against Standard and Hybrid DFT to Model Electronic Properties in Two-Dimensional MOFs for Thermoelectric Applications. J Chem Theory Comput 2024; 20:3976-3992. [PMID: 38708963 PMCID: PMC11100482 DOI: 10.1021/acs.jctc.3c01405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/09/2024] [Accepted: 04/17/2024] [Indexed: 05/07/2024]
Abstract
Recent studies have shown that metal-organic frameworks (MOFs) have potential as thermoelectric materials, and the topic has received increasing attention. The main motivation for this project is to further our knowledge of thermoelectric properties in MOFs and find which available self-consistent-charge density functional tight binding (SCC-DFTB) method can best predict (at least trends in) the electronic properties of MOFs at a lower computational cost than standard density functional theory (DFT). In this work, the electronic properties of monolayer, serrated, AA-stacked, and/or AB-stacked Zn3C6O6, Cd3C6O6, Zn-NH-MOF─for which no previous calculations of thermoelectric performance exist─and Ni3(HITP)2 MOFs are modeled with DFT-PBE, DFT-HSE06, GFN1-xTB, GFN2-xTB, and DFTB-3ob/mio. The band structures, density of states, and their relative orbital contributions, as well as the electrical conductivity, Seebeck coefficient, and power factor, are compared across methods and geometries. Our results suggest that GFN-xTB is adequate to predict the MOFs' band structure shape and density of states but not band gap. Our calculations further indicate that Zn3C6O6, Cd3C6O6, and Zn-NH-MOF have higher power factor values than Ni3(HITP)2, one of the highest performing synthesized MOFs, and are therefore promising for thermoelectric applications.
Collapse
Affiliation(s)
- Masoumeh Mahmoudi Gahrouei
- Department
of Chemistry, University of Wyoming, 1000 E. University Ave., Laramie, Wyoming 82071, United States
| | - Nikiphoros Vlastos
- Department
of Chemistry, University of Wyoming, 1000 E. University Ave., Laramie, Wyoming 82071, United States
| | - Ransell D’Souza
- Department
of Mechanical and Materials Engineering, University of Turku, Turku 20014, Finland
| | - Emmanuel C. Odogwu
- Department
of Chemistry, University of Wyoming, 1000 E. University Ave., Laramie, Wyoming 82071, United States
| | - Laura de Sousa Oliveira
- Department
of Chemistry, University of Wyoming, 1000 E. University Ave., Laramie, Wyoming 82071, United States
| |
Collapse
|
5
|
Erk N, Kurtay G, Bouali W, Sakal ZG, Genç AA, Erbaş Z, Soylak M. Electrochemical Detection of Melphalan in Biological Fluids Using a g-C 3N 4@ND-COOH@MoSe 2 Modified Electrode Complemented by Molecular Docking Studies with Cellular Tumor Antigen P53. ACS OMEGA 2024; 9:21058-21070. [PMID: 38764632 PMCID: PMC11097377 DOI: 10.1021/acsomega.4c00558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/04/2024] [Accepted: 04/16/2024] [Indexed: 05/21/2024]
Abstract
Melphalan (Mel) is a potent alkylating agent utilized in chemotherapy treatments for a diverse range of malignancies. The need for its accurate and timely detection in pharmaceutical preparations and biological samples is paramount to ensure optimized therapeutic efficacy and to monitor treatment progression. To address this critical need, our study introduced a cutting-edge electrochemical sensor. This device boasts a uniquely modified electrode crafted from graphitic carbon nitride (g-C3N4), decorated with activated nanodiamonds (ND-COOH) and molybdenum diselenide (MoSe2), and specifically designed to detect Mel with unparalleled precision. Our rigorous testing employed advanced techniques such as cyclic voltammetry and differential pulse voltammetry. The outcomes were promising; the sensor consistently exhibited a linear response in the range of 0.5 to 12.5 μM. Even more impressively, the detection threshold was as low as 0.03 μM, highlighting its sensitivity. To further enhance our understanding of Mel's biological interactions, we turned to molecular docking studies. These studies primarily focused on Mel's interaction dynamics with the cellular tumor antigen P53, revealing a binding affinity of -5.0 kcal/mol. A fascinating observation was made when Mel was covalently conjugated with nanodiamond-COOH (ND-COOH). This conjugation resulted in a binding affinity that surged to -10.9 kcal/mol, clearly underscoring our sensor's superior detection capabilities. This observation also reinforced the wisdom behind incorporating ND-COOH in our electrode design. In conclusion, our sensor not only stands out in terms of sensitivity but also excels in selectivity and accuracy. By bridging electrochemical sensing with computational insights, our study illuminates Mel's intricate behavior, driving advancements in sensor technology and potentially revolutionizing cancer therapeutic strategies.
Collapse
Affiliation(s)
- Nevin Erk
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560 Ankara, Turkey
| | - Gülbin Kurtay
- Hacettepe University, Faculty of Sciences, Department of Chemistry, 06800 Ankara, Turkey
| | - Wiem Bouali
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560 Ankara, Turkey
- Ankara University, Graduate School of Health Sciences, 06110 Ankara, Turkey
| | - Zeyneb Gülsüm Sakal
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560 Ankara, Turkey
- Ankara University, Graduate School of Health Sciences, 06110 Ankara, Turkey
| | - Asena Ayşe Genç
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560 Ankara, Turkey
- Ankara University, Graduate School of Health Sciences, 06110 Ankara, Turkey
| | - Zeliha Erbaş
- Yozgat Bozok University, Science and Technology Application and Research Center, 66200 Yozgat, Turkey
- Erciyes University, Technology Research & Application Center (TAUM), 38039 Kayseri, Turkey
| | - Mustafa Soylak
- Erciyes University, Technology Research & Application Center (TAUM), 38039 Kayseri, Turkey
- Turkish Academy of Sciences (TUBA), Çankaya, Ankara 06670, Turkey
| |
Collapse
|
6
|
Gillen R, Maultzsch J. Family behavior and Dirac bands in armchair nanoribbons with 4-8 defect lines. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:295501. [PMID: 38579744 DOI: 10.1088/1361-648x/ad3b5a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/05/2024] [Indexed: 04/07/2024]
Abstract
Bottom-up synthesis from molecular precursors is a powerful route for the creation of novel synthetic carbon-based low-dimensional materials, such as planar carbon lattices. The wealth of conceivable precursor molecules introduces a significant number of degrees-of-freedom for the design of materials with defined physical properties. In this context,a prioriknowledge of the electronic, vibrational and optical properties provided by modernab initiosimulation methods can act as a valuable guide for the design of novel synthetic carbon-based building blocks. Using density functional theory, we performed simulations of the electronic properties of armchair-edged graphene nanoribbons (AGNR) with a bisecting 4-8 ring defect line. We show that the electronic structures of the defective nanoribbons of increasing width can be classified into three distinct families of semiconductors, similar to the case of pristine AGNR. In contrast to the latter, we find that every third nanoribbon is a zero-gap semiconductor with Dirac-type crossing of linear bands at the Fermi energy. By employing tight-binding models including interactions up to third-nearest neighbors, we show that the family behavior, the formation of direct and indirect band gaps and of linear band crossings in the defective nanoribbons is rooted in the electronic properties of the individual nanoribbon halves on either side of the defect lines, and can be effectively through introduction of additional 'interhalf' coupling terms.
Collapse
Affiliation(s)
- Roland Gillen
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen, Germany
- College of Engineering, Swansea University, Swansea SA1 8EN, United Kingdom
| | - Janina Maultzsch
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen, Germany
| |
Collapse
|
7
|
Karmakar S, Datta S, Saha-Dasgupta T. First principles predictions of structural, electronic and topological properties of two-dimensional Janus Ti 2N 2XI (X = Br, Cl) structures. Phys Chem Chem Phys 2024; 26:10557-10567. [PMID: 38530661 DOI: 10.1039/d4cp00176a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Motivated by the report of the giant Rashba effect in ternary layered compounds BiTeX, we consider two Janus structured compounds Ti2N2XI (X = Br, Cl) of the same ternary family exhibiting a 1 : 1 : 1 stoichiometric ratio. Broken inversion symmetry in the Janus structure, together with its unique electronic structure exhibiting anti-crossing states formed between Ti-d states and strong spin-orbit coupled I-p states, generates large Rashba cofficients of 2-3 eV Å for these compounds, classifying them as strong Rashba compounds. The anti-crossing features of the first-principles calculated electronic structure also result in non-trivial topology, combining two quantum phenomena - Rashba effect and non-trivial topology - in the same materials. This makes Janus TiNI compounds candidate materials for two-dimensional composite quantum materials. The situation becomes further promising by the fact that the properties are found to exhibit extreme sensitivity and tunability upon application of uniaxial strain.
Collapse
Affiliation(s)
- Shiladitya Karmakar
- S.N. Bose National Centre for Basic Sciences. JD Block, Sector III, Salt Lake, Kolkata 700106, India.
| | - Soumendu Datta
- S.N. Bose National Centre for Basic Sciences. JD Block, Sector III, Salt Lake, Kolkata 700106, India.
| | - Tanusri Saha-Dasgupta
- S.N. Bose National Centre for Basic Sciences. JD Block, Sector III, Salt Lake, Kolkata 700106, India.
| |
Collapse
|
8
|
Bouali W, Kurtay G, Genç AA, Ahmed HEH, Soylak M, Erk N, Karimi-Maleh H. Nanodiamond (ND)-Based ND@CuAl 2O 4@Fe 3O 4 electrochemical sensor for Tofacitinib detection: A unified approach to integrate experimental data with DFT and molecular docking. ENVIRONMENTAL RESEARCH 2023; 238:117166. [PMID: 37741570 DOI: 10.1016/j.envres.2023.117166] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/23/2023] [Accepted: 09/15/2023] [Indexed: 09/25/2023]
Abstract
Tofacitinib (TOF) is gaining recognition as a potent therapeutic agent for a variety of autoimmune disorders, including rheumatoid arthritis and psoriasis. Ensuring precise drug concentration control during treatment necessitates a rapid and sensitive detection method. This study introduces a novel electrochemical sensor employing a composite of nanodiamond (ND), copper aluminate spinel oxide (CuAl2O4), and iron (II, III) oxide (Fe3O4) as modified materials for efficient TOF detection. Extensive analyses using physicochemical and electrochemical techniques were carried out to characterize the morphological, structural, and electrochemical properties of the ND@CuAl2O4@Fe3O4 composite. Thereafter, various voltammetric methods were utilized to evaluate the electrochemical behavior of the ND@CuAl2O4@Fe3O4-modified glassy carbon electrode (GCE) concerning TOF determination. The fabricated electrode showcased superior performance in electrochemical TOF detection in a buffered solution (pH = 5), achieving a remarkably low detection limit of 7.8 nM and a linear response from 0.05 μM to 13.21 μM. Furthermore, applying the modified electrode as an electrochemical sensor exhibited exceptional selectivity, stability, and practicality in determining TOF in pharmaceutical and biological samples. Alongside the sensor development, this study conducted a thorough investigation using Density Functional Theory (DFT) for the geometry optimization of TOF and the TOF-ND complex. Consequently performed molecular docking studies using Janus Kinase 1 (JAK1) (PDB ID: 3EYG) and JAK3 (PDB ID: 3LXK) indicated higher interaction of the TOF-ND conjugate with the JAKs, reflected by binding energies of -12.9 kcal/mol and -11.7 kcal/mol for JAK1 and JAK3 respectively, compared to -7.0 kcal/mol and -6.9 kcal/mol for TOF alone. These findings illustrate the potential of the ND-based ND@CuAl2O4@Fe3O4 composite as a proficient sensing material for TOF detection and the merits of DFT in providing a detailed understanding of the interactions at play. This pioneering research holds promise for real-time TOF monitoring, which will advance personalized treatment strategies and improve therapeutic outcomes for patients with autoimmune disorders.
Collapse
Affiliation(s)
- Wiem Bouali
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560, Ankara, Turkey
| | - Gülbin Kurtay
- Hacettepe University, Faculty of Sciences, Department of Chemistry, 06800, Ankara, Turkey.
| | - Asena Ayşe Genç
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560, Ankara, Turkey
| | | | - Mustafa Soylak
- Technology Research & Application Center (TAUM), Erciyes University, 38039, Kayseri, Turkey; Turkish Academy of Sciences (TUBA), Çankaya, Ankara, Turkey
| | - Nevin Erk
- Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560, Ankara, Turkey.
| | - Hassan Karimi-Maleh
- The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, 324000, China; School of Resources and Environment, University of Electronic Science and Technology of China, P.O. Box 611731, Xiyuan Ave, Chengdu, PR China; School of Engineering, Lebanese American University, Byblos, Lebanon
| |
Collapse
|
9
|
Vysotskiy VP, Torbjörnsson M, Jiang H, Larsson ED, Cao L, Ryde U, Zhai H, Lee S, Chan GKL. Assessment of DFT functionals for a minimal nitrogenase [Fe(SH)4H]- model employing state-of-the-art ab initio methods. J Chem Phys 2023; 159:044106. [PMID: 37486046 DOI: 10.1063/5.0152611] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/03/2023] [Indexed: 07/25/2023] Open
Abstract
We have designed a [Fe(SH)4H]- model with the fifth proton binding either to Fe or S. We show that the energy difference between these two isomers (∆E) is hard to estimate with quantum-mechanical (QM) methods. For example, different density functional theory (DFT) methods give ∆E estimates that vary by almost 140 kJ/mol, mainly depending on the amount of exact Hartree-Fock included (0%-54%). The model is so small that it can be treated by many high-level QM methods, including coupled-cluster (CC) and multiconfigurational perturbation theory approaches. With extrapolated CC series (up to fully connected coupled-cluster calculations with singles, doubles, and triples) and semistochastic heat-bath configuration interaction methods, we obtain results that seem to be converged to full configuration interaction results within 5 kJ/mol. Our best result for ∆E is 101 kJ/mol. With this reference, we show that M06 and B3LYP-D3 give the best results among 35 DFT methods tested for this system. Brueckner doubles coupled cluster with perturbaitve triples seems to be the most accurate coupled-cluster approach with approximate triples. CCSD(T) with Kohn-Sham orbitals gives results within 4-11 kJ/mol of the extrapolated CC results, depending on the DFT method. Single-reference CC calculations seem to be reasonably accurate (giving an error of ∼5 kJ/mol compared to multireference methods), even if the D1 diagnostic is quite high (0.25) for one of the two isomers.
Collapse
Affiliation(s)
- Victor P Vysotskiy
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Magne Torbjörnsson
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Hao Jiang
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Ernst D Larsson
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Lili Cao
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Ulf Ryde
- Department of Computational Chemistry, Lund University, Chemical Centre, SE-221 00 Lund, Sweden
| | - Huanchen Zhai
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Seunghoon Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Garnet Kin-Lic Chan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| |
Collapse
|
10
|
Sharma S, Ward ZD, Bhimani K, Sharma M, Quinton J, Rhone TD, Shi SF, Terrones H, Koratkar N. Machine Learning-Aided Band Gap Engineering of BaZrS 3 Chalcogenide Perovskite. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18962-18972. [PMID: 37014669 DOI: 10.1021/acsami.3c00618] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The non-toxic and stable chalcogenide perovskite BaZrS3 fulfills many key optoelectronic properties for a high-efficiency photovoltaic material. It has been shown to possess a direct band gap with a large absorption coefficient and good carrier mobility values. With a reported band gap of 1.7-1.8 eV, BaZrS3 is a good candidate for tandem solar cell materials; however, its band gap is significantly larger than the optimal value for a high-efficiency single-junction solar cell (∼1.3 eV, Shockley-Queisser limit)─thus doping is required to lower the band gap. By combining first-principles calculations and machine learning algorithms, we are able to identify and predict the best dopants for the BaZrS3 perovskites for potential future photovoltaic devices with a band gap within the Shockley-Queisser limit. It is found that the Ca dopant at the Ba site or Ti dopant at the Zr site is the best candidate dopant. Based on this information, we report for the first time partial doping at the Ba site in BaZrS3 with Ca (i.e., Ba1-xCaxZrS3) and compare its photoluminescence with Ti-doped perovskites [i.e., Ba(Zr1-xTix)S3]. Synthesized (Ba,Ca)ZrS3 perovskites show a reduction in the band gap from ∼1.75 to ∼1.26 eV with <2 atom % Ca doping. Our results indicate that for the purpose of band gap tuning for photovoltaic applications, Ca-doping at the Ba-site is superior to Ti-doping at the Zr-site reported previously.
Collapse
Affiliation(s)
- Shyam Sharma
- Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Zachary D Ward
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Kevin Bhimani
- Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Mukul Sharma
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Joshua Quinton
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Trevor David Rhone
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Su-Fei Shi
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Humberto Terrones
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| | - Nikhil Koratkar
- Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, United States
| |
Collapse
|
11
|
Zhang C, Verma P, Wang J, Liu Y, He X, Wang Y, Truhlar DG, Liu Z. Performance of Screened-Exchange Functionals for Band Gaps and Lattice Constants of Crystals. J Chem Theory Comput 2023; 19:311-323. [PMID: 36520598 DOI: 10.1021/acs.jctc.2c00822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Kohn-Sham density functional theory is the most widely used method for electronic structure calculations of solid-state systems. The screened-exchange functionals developed following the influential work of Scuseria and co-workers in 2003-2006 have significantly improved the accuracy of the predictions of solid-state properties. This work assesses six screened-exchange density functionals for the prediction of 60 band gaps (database BG60) and 68 lattice constants (database LC68). The band gaps are calculated with both consistently calculated lattice constants and experimental lattice constants. Results for the nonlocal screened-exchange functionals are compared with those for six widely used or recently developed local functionals. The results show that all the screened-exchange functionals have smaller mean absolute errors (MAEs) than any of the local functionals. All the functionals except HLE17 overestimate (on average) the lattice constants, and M06-SX gives the best performance among the compared functionals, with a MAE of 0.051 Å. All the functionals underestimate (on average) the band gaps, and M06-SX outperforms all other functionals, with a MAE of 0.47 eV. M06-SX also has the lowest root-mean-squared error for both LC68 and BG60. For the subdatabases of BG60, M06-SX shows better performance for ionic crystals and systems with large band gaps, while HSE12s gives better results for semiconductors and systems with small band gaps. Overall, M06-SX shows the best performance for solid-state systems, followed by N12-SX and HSE12s. The best-performing local functionals are M06-L, revM06-L, and HLE17 for band gaps and M06-L and revM06-L for lattice constants. We found that M06-SX, revM06-L, and N12-SX not only are well optimized for a broad array of chemical properties but also have very good performance for the databases in this paper, making them well-suited for applications involving heterogeneous chemistry.
Collapse
Affiliation(s)
- Cheng Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410006, China
| | - Pragya Verma
- Department of Chemistry, Chemical Theory Center and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Jiaxu Wang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410006, China
| | - Yiwei Liu
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.,New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200062, China
| | - Ying Wang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410006, China
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410006, China
| |
Collapse
|
12
|
Keya KN, Xia W, Kilin D. DFT simulation of conductivity of the p-type doped and charge-injected cis-polyacetylene. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2110167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Kamrun N. Keya
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND, USA
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND, USA
| | - Dmitri Kilin
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND, USA
| |
Collapse
|
13
|
Abstract
Photoluminescence (PL) is one of the key experimental characterizations of optoelectronic materials, including conjugated polymers (CPs). In this study, a simplified model of an undoped cis-polyacetylene (cis-PA) oligomer was selected and used to explain the mechanism of photoluminescence (PL) of the CPs. Using a combination of the ab initio electronic structure and a time-dependent density matrix methodology, the photo-induced time-dependent excited state dynamics were computed. We explored the phonon-induced relaxation of the photoexcited state for a single oligomer of cis-PA. Here, the dissipative Redfield equation of the motion was used to compute the dissipative excited state dynamics of electronic degrees of freedom. This equation used the nonadiabatic couplings as parameters. The computed excited state dynamics showed that the relaxation rate of the electron is faster than the relaxation rate of the hole. The dissipative excited-state dynamics were combined with radiative recombination channels to predict the PL spectrum. The simulated results showed that the absorption and emission spectra both have a similar transition. The main result is that the computed PL spectrum demonstrates two mechanisms of light emission originating from (i) the inter-band transitions, corresponding to the same range of transition energies as the absorption spectrum and (ii) intra-band transitions not available in the absorption spectra. However, the dissipative Redfield equation of the motion was used to compute the electronic degrees of freedom of the nonadiabatic couplings, which helped to process the time propagation of the excited dynamic state. This excited dynamic state shows that the relaxation rate of the electron is faster than the relaxation rate of the hole, which can be used for improving organic semiconductor materials for photovoltaic and LED applications.
Collapse
|
14
|
Shavez M, Panda AN. Assessing Effects of Different π bridges on Properties of Random Benzodithiophene-thienothiophene Donor and Non-fullerene Acceptor Based Active Layer. J Phys Chem A 2021; 125:9852-9864. [PMID: 34738461 DOI: 10.1021/acs.jpca.1c07378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This report presents the effect of insertion of four different π bridges, furan, thienothiophene, thiophene, and thiazole, into a random benzodithiophene (BDT)-fluorinated-thienothiophene (TT-F) based donor. Starting from a structure of synthesized donor (D)-acceptor (A) random copolymer with 3:1 ratio, we have designed four D-π-A systems with four different π bridges. Structural, optoelectronic, and charge transport/transfer properties of these donors and donor/NDI (NDI = poly[N,N'-bis(2-hexyldecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)) blends are investigated using DFT and TD-DFT methodologies. Our results show that the thiazole based TzP1 oligomer has the deepest HOMO value resulting in the highest open circuit voltage among all systems. The maximum absorption wavelengths of π-linked systems are red-shifted compared to the parent molecule. Rates of charge transfer and charge recombination are the highest and smallest in case of the thiazole/NDI blend system. In addition, hole mobilities in thiophene, thienothiophene, and thiazole based systems are larger than in the parent system. The results indicate that the thiazole unit among the four π bridge units is the most suitable for active layer construction.
Collapse
Affiliation(s)
- Mohd Shavez
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Aditya N Panda
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India
| |
Collapse
|
15
|
Alesadi A, Fatima F, Xia W, Kilin D. First-Principles Study on the Electronic Properties of PDPP-Based Conjugated Polymer via Density Functional Theory. J Phys Chem B 2021; 125:8953-8964. [PMID: 34324337 DOI: 10.1021/acs.jpcb.1c02518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this study, we focus on computational predictions of the electronic and optical properties of a one-dimensional periodic model of a single chain of a diketopyrrolopyrrole (DPP)-based conjugated polymer (PDPP3T) as a function of electronic configuration changes due to charge injection. We employ density functional theory (DFT) to explore the ground-state and excited-state electronic properties as well as optical properties influenced by charge injection. We utilize both the Heyd-Scuseria-Ernzerhof (HSE06) and Perdew-Burke-Ernzerhof (PBE) functionals to predict the band gap and compute the absorption spectrum. Our DFT results point out that utilizing the HSE06 functional in conjunction with momentum sampling over the Brillouin zone can appropriately predict the band gap and absorption spectrum in good agreement with experimental data. Moreover, we explore the influence of charge-carrier injection on the electronic configuration of the PDPP3T polymer. Our results indicate that the injection of charge carriers into the PDPP3T semiconducting polymer model greatly affects the electrical properties and ends in a low band gap and high mobility of charge carriers in PDPP3T polymers, offering the potential to tailor the material electronic performance for organic photovoltaic and optoelectronic device applications.
Collapse
Affiliation(s)
- Amirhadi Alesadi
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| | - F Fatima
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States.,Materials and Nanotechnology, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Dmitri Kilin
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
| |
Collapse
|
16
|
Shavez M, Ray AK, Panda AN. Halogenation of the Side Chains in Donor‐Acceptor Based Small Molecules for Photovoltaic Applications: Energetics and Charge‐Transfer Properties from DFT/TDDFT Studies. ChemistrySelect 2021. [DOI: 10.1002/slct.202100921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mohd Shavez
- Department of Chemistry Indian Institute of Technology Guwahati Guwahati 781039 India
| | - Anuj Kumar Ray
- Department of Chemistry Indian Institute of Technology Guwahati Guwahati 781039 India
| | - Aditya N. Panda
- Department of Chemistry Indian Institute of Technology Guwahati Guwahati 781039 India
| |
Collapse
|
17
|
Kick M, Scheurer C, Oberhofer H. Formation and stability of small polarons at the lithium-terminated Li 4Ti 5O 12 (LTO) (111) surface. J Chem Phys 2020; 153:144701. [PMID: 33086832 DOI: 10.1063/5.0021443] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Zero strain insertion, high cycling stability, and a stable charge/discharge plateau are promising properties rendering Lithium Titanium Oxide (LTO) a possible candidate for an anode material in solid state Li ion batteries. However, the use of pristine LTO in batteries is rather limited due to its electronically insulating nature. In contrast, reduced LTO shows an electronic conductivity several orders of magnitude higher. Studying bulk reduced LTO, we could show recently that the formation of polaronic states can play a major role in explaining this improved conductivity. In this work, we extend our study toward the lithium-terminated LTO (111) surface. We investigate the formation of polarons by applying Hubbard-corrected density functional theory. Analyzing their relative stabilities reveals that positions with Li ions close by have the highest stability among the different localization patterns.
Collapse
Affiliation(s)
- Matthias Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Christoph Scheurer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching, Germany
| |
Collapse
|
18
|
Shavez M, Panda AN. Effects of π-bridge units on the properties of donor-π-acceptor type benzodithiophene-thienothiophene based polymers for organic solar cells. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
19
|
Krasnov AG, Napalkov MS, Vlasov MI, Koroleva MS, Shein IR, Piir IV. Photocatalytic Properties of Bi 2-xTi 2O 7-1.5x ( x = 0, 0.5) Pyrochlores: Hybrid DFT Calculations and Experimental Study. Inorg Chem 2020; 59:12385-12396. [PMID: 32806001 DOI: 10.1021/acs.inorgchem.0c01472] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The photocatalytic properties of Bi2-xTi2O7-1.5x (x = 0, 0.5) pyrochlores are examined via ab initio calculations and experiments. A coprecipitation method is applied for the synthesis of nanopowder pyrochlores. The pyrochlore phase formation starts at 500 °C (Bi2Ti2O7) and 550 °C (Bi1.5Ti2O6.25). Nanopowders are found to be a metastable character of pyrochlore phases. The presence of bismuth and oxygen vacancies enhances the thermal stability of the Bi1.5Ti2O6.25 phase in comparison with the Bi2Ti2O7 phase. The estimated crystallite size is 30-40 nm with noticeable agglomerates of about 100-300 nm according to scanning electron microscopy (SEM) and with the formation of particles (510-580 nm) in the aqueous medium. The isoelectric points of the nanopowders seem to be shifted to the strongly acidic region, resulting in the formation of negative surface particle charges of -33 mV (Bi2Ti2O7) and -27 mV (Bi1.5Ti2O6.25) at pH 5.88 in distilled water. The specific surface area is 11.5 m2/g (Bi2Ti2O7) and 12.00 m2/g (Bi1.5Ti2O6.25). The use of the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) functional allows achieving an excellent agreement between theoretical and experimental structural parameters. The screened Coulomb hybrid HSE03 functional is the most appropriate for describing the optoelectronic properties. Bismuth titanate pyrochlores are wide-gap semiconductors with strong abilities to be active photocatalysts under visible irradiation. The optical Eg values for direct/indirect transition according to the experiment, 3.19/2.94 eV (x = 0) and 3.24/3.03 eV (x = 0.5), and the DFT/HSE03 calculations, 2.92/2.87 (x = 0) and 3.42/- eV (x = 0.5), are in the visible light region and are close. The calculated low effective masses of the charge carriers and suitable band edge positions confirm the ability of the pyrochlores to act as photocatalysts. The photocatalytic activity has been evaluated through the decomposition of rhodamine B under visible irradiation. Bi2Ti2O7 shows the highest activity in comparison with Bi1.5Ti2O6.25, which is in good agreement with theoretically predicted and experimentally revealed characteristics.
Collapse
Affiliation(s)
- Aleksei G Krasnov
- Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Maxim S Napalkov
- Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Syktyvkar State University, Syktyvkar, Russia
| | - Maxim I Vlasov
- Ural Federal University, NANOTECH Center, Ekaterinburg, Russia.,Institute of High Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences, Ekaterinburg, Russia
| | - Mariia S Koroleva
- Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Igor R Shein
- Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, Ekaterinburg, Russia
| | - Irina V Piir
- Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| |
Collapse
|
20
|
Venturi V, Parks HL, Ahmad Z, Viswanathan V. Machine learning enabled discovery of application dependent design principles for two-dimensional materials. MACHINE LEARNING-SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1088/2632-2153/aba002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
21
|
Abstract
In view of their applicability in optoelectronics, we review here the relevant structural, electronic, and optical features of the inorganic Pb-free halide perovskite class. In particular, after discussing the reasons that have motivated their introduction in opposition to their more widely investigated organic-inorganic counterparts, we highlight milestones already achieved in their synthesis and characterization and show how the use of ab initio ground and excited state methods is relevant in predicting their properties and in disclosing yet unsolved issues which characterize both ternary and quaternary stoichiometry double-perovskites.
Collapse
|
22
|
Cipriano LA, Di Liberto G, Tosoni S, Pacchioni G. Band Gap in Magnetic Insulators from a Charge Transition Level Approach. J Chem Theory Comput 2020; 16:3786-3798. [PMID: 32427487 PMCID: PMC8007096 DOI: 10.1021/acs.jctc.0c00134] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Indexed: 11/30/2022]
Abstract
The theoretical description of the electronic structure of magnetic insulators and, in particular, of transition-metal oxides (TMOs), MnO, FeO, CoO, NiO, and CuO, poses several problems due to their highly correlated nature. Particularly challenging is the determination of the band gap. The most widely used approach is based on density functional theory (DFT) Kohn-Sham energy levels using self-interaction-corrected functionals (such as hybrid functionals). Here, we present a different approach based on the assumption that the band gap in some TMOs can have a partial Mott-Hubbard character and can be defined as the energy associated with the process Mm+(3dn) + Mm+(3dn) → M(m+1)+(3dn-1) + M(m-1)+(3dn+1). The band gap is thus associated with the removal (ionization potential, I) and addition (electron affinity, A) of one electron to an ion of the lattice. In fact, due to the hybridization of metal with ligand orbitals, these energy contributions are not purely atomic in nature. I and A can be computed accurately using the charge transition level (CTL) scheme. This procedure is based on the calculation of energy levels of charged states and goes beyond the approximations inherent to the Kohn-Sham (KS) approach. The novel and relevant aspect of this work is the extension of CTLs from the domain of point defects to a bulk property such as the band gap. The results show that the calculation based on CTLs provides band gaps in better agreement with experiments than the KS approach, with direct insight into the nature of the gap in these complex systems.
Collapse
Affiliation(s)
- Luis A. Cipriano
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Giovanni Di Liberto
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei
Materiali, Università di Milano—Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| |
Collapse
|
23
|
Kick M, Grosu C, Schuderer M, Scheurer C, Oberhofer H. Mobile Small Polarons Qualitatively Explain Conductivity in Lithium Titanium Oxide Battery Electrodes. J Phys Chem Lett 2020; 11:2535-2540. [PMID: 32162917 DOI: 10.1021/acs.jpclett.0c00568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lithium titanium oxide Li4Ti5O12 is an intriguing anode material promising particularly long-life batteries, due to its remarkable phase stability during (dis)charging of the cell. However, its usage is limited by its low intrinsic electronic conductivity. Introducing oxygen vacancies can be one method for overcoming this drawback, possibly by altering the charge carrier transport mechanism. We use Hubbard corrected density functional theory to show that polaronic states in combination with a possible hopping mechanism can play a crucial role in the experimentally observed increase in electronic conductivity. To gauge polaronic charge mobility, we compute the relative stabilities of different localization patterns and estimate polaron hopping barrier heights.
Collapse
Affiliation(s)
- Matthias Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Cristina Grosu
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
- Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Markus Schuderer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Christoph Scheurer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany
| |
Collapse
|
24
|
Wolff S, Gillen R, Assebban M, Abellán G, Maultzsch J. Two-Dimensional Antimony Oxide. PHYSICAL REVIEW LETTERS 2020; 124:126101. [PMID: 32281827 DOI: 10.1103/physrevlett.124.126101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Two-dimensional (2D) antimony, so-called antimonene, can form antimonene oxide when exposed to air. We present different types of single- and few-layer antimony oxide structures, based on density functional theory (DFT) calculations. Depending on stoichiometry and bonding type, these novel 2D layers have different structural stability and electronic properties, ranging from topological insulators to semiconductors with direct and indirect band gaps between 2.0 and 4.9 eV. We discuss their vibrational properties and Raman spectra for experimental identification of the predicted structures.
Collapse
Affiliation(s)
- Stefan Wolff
- Department of Physics, Chair of Experimental Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany
| | - Roland Gillen
- Department of Physics, Chair of Experimental Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany
| | - Mhamed Assebban
- Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Valencia, Spain
- Department of Chemistry and Pharmacy & Joint Institute of Advanced Materials and Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg, Dr.-Mack-Straße 81, 90762 Fürth, Germany
| | - Gonzalo Abellán
- Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Valencia, Spain
- Department of Chemistry and Pharmacy & Joint Institute of Advanced Materials and Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg, Dr.-Mack-Straße 81, 90762 Fürth, Germany
| | - Janina Maultzsch
- Department of Physics, Chair of Experimental Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany
| |
Collapse
|
25
|
Pishtshev A, Strugovshchikov E, Karazhanov S. On Prediction of a Novel Chiral Material Y 2H 3O(OH): A Hydroxyhydride Holding Hydridic and Protonic Hydrogens. MATERIALS (BASEL, SWITZERLAND) 2020; 13:ma13040994. [PMID: 32098454 PMCID: PMC7078701 DOI: 10.3390/ma13040994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/06/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Examination of possible pathways of how oxygen atoms can be added to a yttrium oxyhydride system allowed us to predict new derivatives such as hydroxyhydrides possessing the composition M2H3O(OH) (M = Y, Sc, La, and Gd) in which three different anions (H-, O2-, and OH-) share the common chemical space. The crystal data of the solid hydroxyhydrides obtained on the base of DFT modeling correspond to the tetragonal structure that is characterized by the chiral space group P 4 1 . The analysis of bonding situation in M2H3O(OH) showed that the microscopic mechanism governing chemical transformations is caused by the displacements of protons which are induced by interaction with oxygen atoms incorporated into the crystal lattice of the bulk oxyhydride. The oxygen-mediated transformation causes a change in the charge state of some adjacent hydridic sites, thus forming protonic sites associated with hydroxyl groups. The predicted materials demonstrate a specific charge ordering that is associated with the chiral structural organization of the metal cations and the anions because their lattice positions form helical curves spreading along the tetragonal axis. Moreover, the effect of spatial twisting of the H- and H+ sites provides additional linking via strong dihydrogen bonds. The structure-property relationships have been investigated in terms of structural, mechanical, electron, and optical features. It was shown that good polar properties of the materials make them possible prototypes for the design of nonlinear optical systems.
Collapse
Affiliation(s)
- Aleksandr Pishtshev
- Institute of Physics, University of Tartu, W.Ostwaldi 1, 50411 Tartu, Estonia;
| | | | - Smagul Karazhanov
- Department for Solar Energy, Institute for Energy Technology, 2007 Kjeller, Norway;
| |
Collapse
|
26
|
Wang Y, Verma P, Zhang L, Li Y, Liu Z, Truhlar DG, He X. M06-SX screened-exchange density functional for chemistry and solid-state physics. Proc Natl Acad Sci U S A 2020; 117:2294-2301. [PMID: 31953258 PMCID: PMC7007546 DOI: 10.1073/pnas.1913699117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Screened-exchange hybrid density functionals are especially recommended for solid-state systems because they combine the advantages of hybrid functionals with the correct physics and lower computational cost associated with the attenuation of Hartree-Fock exchange at long range. We present a screened-exchange hybrid functional, M06-SX, that combines the functional form of the local revM06-L functional with a percentage of short-range nonlocal Hartree-Fock exchange. The M06-SX functional gives good results not only for a large set of training data but also for several databases quite different from the training data. The mean unsigned error (MUE) of the M06-SX functional is 2.85 kcal/mol for 418 atomic and molecular energies (AME418) in Minnesota Database 2019, which is better than all five other screened-exchange hybrid functionals tested in this work. The M06-SX functional also gives especially good results for semiconductor band gaps, molecular dissociation energies, noncovalent interactions, barrier heights, and electronic excitation energies excluding long-range charge transfer excitations. For the LC18 lattice constants database, the M06-SX functional gives an MUE of only 0.034 Å. Therefore, the M06-SX functional is well suited for studying molecular chemistry as well as solid-state physics.
Collapse
Affiliation(s)
- Ying Wang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410006, China
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Pragya Verma
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455-0431
- Chemical Theory Center, University of Minnesota, Minneapolis, MN 55455-0431
- Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, MN 55455-0431
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
- New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200062, China
| | - Yaqi Li
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410006, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410006, China
| | - Donald G Truhlar
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455-0431;
- Chemical Theory Center, University of Minnesota, Minneapolis, MN 55455-0431
- Nanoporous Materials Genome Center, University of Minnesota, Minneapolis, MN 55455-0431
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China;
- New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200062, China
| |
Collapse
|
27
|
Liu P, Franchini C, Marsman M, Kresse G. Assessing model-dielectric-dependent hybrid functionals on the antiferromagnetic transition-metal monoxides MnO, FeO, CoO, and NiO. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:015502. [PMID: 31484169 DOI: 10.1088/1361-648x/ab4150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recently, two nonempirical hybrid functionals, dielectric-dependent range-separated hybrid functional based on the Coulomb-attenuating method (DD-RSH-CAM) and doubly screened hybrid functional (DSH), have been suggested by Chen et al (2018 Phys. Rev. Mater. 2 073803) and Cui et al (2018 J. Phys. Chem. Lett. 9 2338), respectively. These two hybrid functionals are both based on a common model dielectric function approach, but differ in the way how to non-empirically obtain the range-separation parameter. By retaining the full short-range Fock exchange and a fraction of the long-range Fock exchange that equals the inverse of the dielectric constant, both DD-RSH-CAM and DSH turn out to perform very well in predicting the band gaps for a large variety of semiconductors and insulators. Here, we assess how these two hybrid functionals perform on challenging antiferromagnetic transition-metal monoxides MnO, FeO, CoO, and NiO by comparing them to other conventional hybrid functionals and the GW method. We find that single-shot DD0-RSH-CAM and DSH0 improve the band gaps towards experiments as compared to conventional hybrid functionals. The magnetic moments are slightly increased, but the predicted dielectric constants are decreased. The valence band density of states (DOS) predicted by DD0-RSH-CAM and DSH0 are as satisfactory as HSE03 in comparison to experimental spectra, however, the conduction band DOS are shifted to higher energies by about 2 eV compared to HSE03. Self-consistent DD-RSH-CAM and DSH deteriorate the results with a significant overestimation of band gaps.
Collapse
Affiliation(s)
- Peitao Liu
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Sensengasse 8, A-1090 Vienna, Austria
| | | | | | | |
Collapse
|
28
|
Karni O, Barré E, Lau SC, Gillen R, Ma EY, Kim B, Watanabe K, Taniguchi T, Maultzsch J, Barmak K, Page RH, Heinz TF. Infrared Interlayer Exciton Emission in MoS_{2}/WSe_{2} Heterostructures. PHYSICAL REVIEW LETTERS 2019; 123:247402. [PMID: 31922842 DOI: 10.1103/physrevlett.123.247402] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Indexed: 05/12/2023]
Abstract
We report light emission around 1 eV (1240 nm) from heterostructures of MoS_{2} and WSe_{2} transition metal dichalcogenide monolayers. We identify its origin in an interlayer exciton (ILX) by its wide spectral tunability under an out-of-plane electric field. From the static dipole moment of the state, its temperature and twist-angle dependence, and comparison with electronic structure calculations, we assign this ILX to the fundamental interlayer transition between the K valleys in this system. Our findings gain access to the interlayer physics of the intrinsically incommensurate MoS_{2}/WSe_{2} heterostructure, including moiré and valley pseudospin effects, and its integration with silicon photonics and optical fiber communication systems operating at wavelengths longer than 1150 nm.
Collapse
Affiliation(s)
- Ouri Karni
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Elyse Barré
- Department of Electrical Engineering, Stanford University, Stanford, California, 94305, USA
| | - Sze Cheung Lau
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Roland Gillen
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudstrasse 7, 91058 Erlangen, Germany
| | - Eric Yue Ma
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - Bumho Kim
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Janina Maultzsch
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudstrasse 7, 91058 Erlangen, Germany
| | - Katayun Barmak
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - Ralph H Page
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - Tony F Heinz
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| |
Collapse
|
29
|
Shavez M, Goswami J, Panda AN. Effect of fluorination of the donor unit on the properties of benzodithiophene-triazole based donor-acceptor systems for polymer solar cells: A computational investigation. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.112564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
30
|
|
31
|
Dittmer A, Izsák R, Neese F, Maganas D. Accurate Band Gap Predictions of Semiconductors in the Framework of the Similarity Transformed Equation of Motion Coupled Cluster Theory. Inorg Chem 2019; 58:9303-9315. [PMID: 31240911 PMCID: PMC6750750 DOI: 10.1021/acs.inorgchem.9b00994] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
In
this work, we present a detailed comparison between wave-function-based
and particle/hole techniques for the prediction of band gap energies
of semiconductors. We focus on the comparison of the back-transformed
Pair Natural Orbital Similarity Transformed Equation of Motion Coupled-Cluster
(bt-PNO-STEOM-CCSD) method with Time Dependent Density Functional
Theory (TD-DFT) and Delta Self Consistent Field/DFT (Δ-SCF/DFT)
that are employed to calculate the band gap energies in a test set
of organic and inorganic semiconductors. Throughout, we have used
cluster models for the calculations that were calibrated by comparing
the results of the cluster calculations to periodic DFT calculations
with the same functional. These calibrations were run with cluster
models of increasing size until the results agreed closely with the
periodic calculation. It is demonstrated that bt-PNO-STEOM-CC yields
accurate results that are in better than 0.2 eV agreement with the
experiment. This holds for both organic and inorganic semiconductors.
The efficiency of the employed computational protocols is thoroughly
discussed. Overall, we believe that this study is an important contribution
that can aid future developments and applications of excited state
coupled cluster methods in the field of solid-state chemistry and
heterogeneous catalysis. In this work, it is shown
that a combination of the embedded cluster approach with wave-function-based
ab initio methods in the framework of the Similarity Transformed Equation
of Motion Coupled Cluster (bt-PNO STEOM-CC) provides an accurate protocol
for band gap energy predictions in classes of organic and inorganic
semiconductors.
Collapse
Affiliation(s)
- Anneke Dittmer
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Róbert Izsák
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Dimitrios Maganas
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany
| |
Collapse
|
32
|
Kick M, Reuter K, Oberhofer H. Intricacies of DFT+U, Not Only in a Numeric Atom Centered Orbital Framework. J Chem Theory Comput 2019; 15:1705-1718. [DOI: 10.1021/acs.jctc.8b01211] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthias Kick
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
| | - Karsten Reuter
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
| | - Harald Oberhofer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, Garching 85747, Germany
| |
Collapse
|
33
|
Moses Abraham B, Adivaiah B, Vaitheeswaran G. Microscopic origin of pressure-induced phase-transitions in urea: a detailed investigation through first principles calculations. Phys Chem Chem Phys 2019; 21:884-900. [PMID: 30560262 DOI: 10.1039/c8cp04827d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The potential crystal structures and properties of urea as a function of pressure were studied using ab initio based electronic structure calculations. The enthalpy-pressure behavior shows that urea undergoes a pressure induced structural phase transition from P4[combining macron]21m (phase I) → P212121 (phase III) at 0.66 GPa with a volume collapse of 4.83%, driven by softening of the acoustic mode along the Γ-X direction. Another phase transition from the P212121 → P21212 structure was identified at 3.09 GPa. The violation of Born stability criteria in the P212121 structure along with softening of the acoustic mode in the U-R direction was responsible for the pressure induced phase transition. Furthermore, the application of pressure led to the breaking and formation of N-HO bonds in the crystal structure of urea during the phase transition, i.e., the H-acceptor capacitance of the oxygen atoms was varied between phases I/IV and -III. Band structure calculations were performed using a hybrid functional (Heyd, Scuseria and Ernzerhof, HSE) which includes a part of exact Fock-exchange. The computed electronic band structure showed that the urea polymorphs are insulators with a direct band gap of 6.21, 6.85 and 6.99 eV for phase-I, -III and -IV, respectively, at selected pressures. We have also presented the dielectric functions (real (ε1(ω)) and imaginary (ε2(ω)) parts), refractive index and absorption coefficients to explore the optical characteristics of the urea phases. The geometric interpretation of intermolecular interactions were quantitatively visualized using Hirshfeld surface analysis. Our results provide a complete picture of various properties of urea polymorphs that lay the foundation for further understanding of structures and their applications.
Collapse
Affiliation(s)
- B Moses Abraham
- Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad-500046, Telangana, India.
| | | | | |
Collapse
|
34
|
Wu D, Wang S, Zhang S, Liu Y, Ding Y, Yang B, Chen H. Stabilization of two-dimensional penta-silicene for flexible lithium-ion battery anodes via surface chemistry reconfiguration. Phys Chem Chem Phys 2019; 21:1029-1037. [PMID: 30311925 DOI: 10.1039/c8cp05008b] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Surface chemistry reconfiguration is employed to acquire stable penta-silicene with tunable properties for use in flexible lithium-ion battery anodes.
Collapse
Affiliation(s)
- Donghai Wu
- Henan Provincial Key Laboratory of Nanocomposites and Applications
- Institute of Nanostructured Functional Materials
- Huanghe Science and Technology College
- Zhengzhou 450006
- China
| | - Shuaiwei Wang
- Henan Provincial Key Laboratory of Nanocomposites and Applications
- Institute of Nanostructured Functional Materials
- Huanghe Science and Technology College
- Zhengzhou 450006
- China
| | - Shouren Zhang
- Henan Provincial Key Laboratory of Nanocomposites and Applications
- Institute of Nanostructured Functional Materials
- Huanghe Science and Technology College
- Zhengzhou 450006
- China
| | - Yibiao Liu
- Henan Provincial Key Laboratory of Nanocomposites and Applications
- Institute of Nanostructured Functional Materials
- Huanghe Science and Technology College
- Zhengzhou 450006
- China
| | - Yingchun Ding
- College of Optoelectronics Technology
- Chengdu University of Information Technology
- Chengdu
- China
| | - Baocheng Yang
- Henan Provincial Key Laboratory of Nanocomposites and Applications
- Institute of Nanostructured Functional Materials
- Huanghe Science and Technology College
- Zhengzhou 450006
- China
| | - Houyang Chen
- Department of Chemical and Biological Engineering
- State University of New York at Buffalo
- Buffalo
- New York 14260-4200
- USA
| |
Collapse
|
35
|
Lekin K, Leitch AA, Assoud A, Yong W, Desmarais J, Tse JS, Desgreniers S, Secco RA, Oakley RT. Benzoquinone-Bridged Heterocyclic Zwitterions as Building Blocks for Molecular Semiconductors and Metals. Inorg Chem 2018; 57:4757-4770. [PMID: 29620356 DOI: 10.1021/acs.inorgchem.8b00485] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In pursuit of closed-shell building blocks for single-component organic semiconductors and metals, we have prepared benzoquino-bis-1,2,3-thiaselenazole QS, a heterocyclic selenium-based zwitterion with a small gap (λmax = 729 nm) between its highest occupied and lowest unoccupied molecular orbitals. In the solid state, QS exists in two crystalline phases and one nanocrystalline phase. The structures of the crystalline phases (space groups R3 c and P21/ c) have been determined by high-resolution powder X-ray diffraction methods at ambient and elevated pressures (0-15 GPa), and their crystal packing patterns have been compared with that of the related all-sulfur zwitterion benzoquino-bis-1,2,3-dithiazole QT (space group Cmc21). Structural differences between the S- and Se-based materials are interpreted in terms of local intermolecular S/Se···N'/O' secondary bonding interactions, the strength of which varies with the nature of the chalcogen (S vs Se). While the perfectly two-dimensional "brick-wall" packing pattern associated with the Cmc21 phase of QT is not found for QS, all three phases of QS are nonetheless small band gap semiconductors, with σRT ranging from 10-5 S cm-1 for the P21/ c phase to 10-3 S cm-1 for the R3 c phase. The bandwidths of the valence and conduction bands increase with applied pressure, leading to an increase in conductivity and a decrease in thermal activation energy Eact. For the R3 c phase, band gap closure to yield an organic molecular metal with a σRT of ∼102 S cm-1 occurs at 6 GPa. Band gaps estimated from density functional theory band structure calculations on the ambient- and high-pressure crystal structures of QT and QS correlate well with those obtained experimentally.
Collapse
Affiliation(s)
- Kristina Lekin
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Alicea A Leitch
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Abdeljalil Assoud
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Wenjun Yong
- Department of Earth Sciences , University of Western Ontario , London , Ontario N6A 5B7 , Canada
| | - Jacques Desmarais
- Department of Physics , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - John S Tse
- Department of Physics , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Serge Desgreniers
- Department of Physics , University of Ottawa , Ottawa , Ontario K1N 6N5 , Canada
| | - Richard A Secco
- Department of Earth Sciences , University of Western Ontario , London , Ontario N6A 5B7 , Canada
| | - Richard T Oakley
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| |
Collapse
|
36
|
Dovesi R, Erba A, Orlando R, Zicovich‐Wilson CM, Civalleri B, Maschio L, Rérat M, Casassa S, Baima J, Salustro S, Kirtman B. Quantum‐mechanical condensed matter simulations with CRYSTAL. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1360] [Citation(s) in RCA: 834] [Impact Index Per Article: 139.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | | | | | | | | | | | - Michel Rérat
- Equipe de Chimie Physique, IPREM UMR5254Université de Pau et des Pays de l’AdourPauFrance
| | | | - Jacopo Baima
- Dipartimento di ChimicaUniversità di TorinoTorinoItaly
| | | | - Bernard Kirtman
- Department of Chemistry and BiochemistryUniversity of CaliforniaSanta Barbara, California
| |
Collapse
|
37
|
Bashyal K, Pyles CK, Afroosheh S, Lamichhane A, Zayak AT. Empirical optimization of DFT + U and HSE for the band structure of ZnO. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:065501. [PMID: 29327688 DOI: 10.1088/1361-648x/aaa441] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
ZnO is a well-known wide band gap semiconductor with promising potential for applications in optoelectronics, transparent electronics, and spintronics. Computational simulations based on the density functional theory (DFT) play an important role in the research of ZnO, but the standard functionals, like Perdew-Burke-Erzenhof, result in largely underestimated values of the band gap and the binding energies of the Zn3d electrons. Methods like DFT + U and hybrid functionals are meant to remedy the weaknesses of plain DFT. However, both methods are not parameter-free. Direct comparison with experimental data is the best way to optimize the computational parameters. X-ray photoemission spectroscopy (XPS) is commonly considered as a benchmark for the computed electronic densities of states. In this work, both DFT + U and HSE methods were parametrized to fit almost exactly the binding energies of electrons in ZnO obtained by XPS. The optimized parameterizations of DFT + U and HSE lead to significantly worse results in reproducing the ion-clamped static dielectric tensor, compared to standard high-level calculations, including GW, which in turn yield a perfect match for the dielectric tensor. The failure of our XPS-based optimization reveals the fact that XPS does not report the ground state electronic structure for ZnO and should not be used for benchmarking ground state electronic structure calculations.
Collapse
Affiliation(s)
- Keshab Bashyal
- Department of Physics and Astronomy, Bowling Green State University, Bowling Green, OH 43403, United States of America
| | | | | | | | | |
Collapse
|
38
|
Foster ME, Sohlberg K, Allendorf MD, Talin AA. Unraveling the Semiconducting/Metallic Discrepancy in Ni 3(HITP) 2. J Phys Chem Lett 2018; 9:481-486. [PMID: 29316790 DOI: 10.1021/acs.jpclett.7b03140] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 is a π-stacked layered metal-organic framework material with extended π-conjugation that is analogous to graphene. Published experimental results indicate that the material is semiconducting, but all theoretical studies to date predict the bulk material to be metallic. Given that previous experimental work was carried out on specimens containing complex nanocrystalline microstructures and the tendency for internal interfaces to introduce transport barriers, we apply DFT to investigate the influence of internal interface defects on the electronic structure of Ni3(HITP)2. The results show that interface defects can introduce a transport barrier by breaking the π-conjugation and/or decreasing the dispersion of the electronic bands near the Fermi level. We demonstrate that the presence of defects can open a small gap, in the range of 15-200 meV, which is consistent with the experimentally inferred hopping barrier.
Collapse
Affiliation(s)
- Michael E Foster
- Sandia National Laboratories , Livermore, California 94551-0969, United States
| | - Karl Sohlberg
- Department of Chemistry, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Mark D Allendorf
- Sandia National Laboratories , Livermore, California 94551-0969, United States
| | - A Alec Talin
- Sandia National Laboratories , Livermore, California 94551-0969, United States
| |
Collapse
|
39
|
Gerosa M, Bottani CE, Di Valentin C, Onida G, Pacchioni G. Accuracy of dielectric-dependent hybrid functionals in the prediction of optoelectronic properties of metal oxide semiconductors: a comprehensive comparison with many-body GW and experiments. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:044003. [PMID: 29087359 DOI: 10.1088/1361-648x/aa9725] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding the electronic structure of metal oxide semiconductors is crucial to their numerous technological applications, such as photoelectrochemical water splitting and solar cells. The needed experimental and theoretical knowledge goes beyond that of pristine bulk crystals, and must include the effects of surfaces and interfaces, as well as those due to the presence of intrinsic defects (e.g. oxygen vacancies), or dopants for band engineering. In this review, we present an account of the recent efforts in predicting and understanding the optoelectronic properties of oxides using ab initio theoretical methods. In particular, we discuss the performance of recently developed dielectric-dependent hybrid functionals, providing a comparison against the results of many-body GW calculations, including G 0 W 0 as well as more refined approaches, such as quasiparticle self-consistent GW. We summarize results in the recent literature for the band gap, the band level alignment at surfaces, and optical transition energies in defective oxides, including wide gap oxide semiconductors and transition metal oxides. Correlated transition metal oxides are also discussed. For each method, we describe successes and drawbacks, emphasizing the challenges faced by the development of improved theoretical approaches. The theoretical section is preceded by a critical overview of the main experimental techniques needed to characterize the optoelectronic properties of semiconductors, including absorption and reflection spectroscopy, photoemission, and scanning tunneling spectroscopy (STS).
Collapse
Affiliation(s)
- M Gerosa
- Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, United States of America
| | | | | | | | | |
Collapse
|
40
|
Ivády V, Gali A, Abrikosov IA. Hybrid-DFT + V w method for band structure calculation of semiconducting transition metal compounds: the case of cerium dioxide. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:454002. [PMID: 28891806 DOI: 10.1088/1361-648x/aa8b93] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hybrid functionals' non-local exchange-correlation potential contains a derivative discontinuity that improves on standard semi-local density functional theory (DFT) band gaps. Moreover, by careful parameterization, hybrid functionals can provide self-interaction reduced description of selected states. On the other hand, the uniform description of all the electronic states of a given system is a known drawback of these functionals that causes varying accuracy in the description of states with different degrees of localization. This limitation can be remedied by the orbital dependent exact exchange extension of hybrid functionals; the hybrid-DFT + V w method (Ivády et al 2014 Phys. Rev. B 90 035146). Based on the analogy of quasi-particle equations and hybrid-DFT single particle equations, here we demonstrate that parameters of hybrid-DFT + V w functional can be determined from approximate theoretical quasi-particle spectra without any fitting to experiment. The proposed method is illustrated on the charge self-consistent electronic structure calculation for cerium dioxide where itinerant valence states interact with well-localized 4f atomic like states, making this system challenging for conventional methods, either hybrid-DFT or LDA + U, and therefore allowing for a demonstration of the advantages of the proposed scheme.
Collapse
Affiliation(s)
- Viktor Ivády
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden. Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525, Budapest, Hungary
| | | | | |
Collapse
|
41
|
He J, Franchini C. Assessing the performance of self-consistent hybrid functional for band gap calculation in oxide semiconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:454004. [PMID: 28812543 DOI: 10.1088/1361-648x/aa867e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper we assess the predictive power of the self-consistent hybrid functional scPBE0 in calculating the band gap of oxide semiconductors. The computational procedure is based on the self-consistent evaluation of the mixing parameter α by means of an iterative calculation of the static dielectric constant using the perturbation expansion after discretization method and making use of the relation [Formula: see text]. Our materials dataset is formed by 30 compounds covering a wide range of band gaps and dielectric properties, and includes materials with a wide spectrum of applications such as thermoelectrics, photocatalysis, photovoltaics, transparent conducting oxides, and refractory materials. Our results show that the scPBE0 functional provides better band gaps than the non self-consistent hybrids PBE0 and HSE06, but scPBE0 does not show significant improvement on the description of the static dielectric constants. Overall, the scPBE0 data exhibit a mean absolute percentage error of 14% (band gaps) and 10% ([Formula: see text]). For materials with weak dielectric screening and large excitonic biding energies scPBE0, unlike PBE0 and HSE06, overestimates the band gaps, but the value of the gap becomes very close to the experimental value when excitonic effects are included (e.g. for SiO2). However, special caution must be given to the compounds with small band gaps due to the tendency of scPBE0 to overestimate the dielectric constant in the proximity of the metallic limit.
Collapse
Affiliation(s)
- Jiangang He
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, Vienna, Austria. Department of Materials Science and Engineering, Northwestern University, Evanston, IL, United States of America
| | | |
Collapse
|
42
|
Sundararaman R, Letchworth-Weaver K, Schwarz KA, Gunceler D, Ozhabes Y, Arias T. JDFTx: software for joint density-functional theory. SOFTWAREX 2017; 6:278-284. [PMID: 29892692 PMCID: PMC5992620 DOI: 10.1016/j.softx.2017.10.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Density-functional theory (DFT) has revolutionized computational prediction of atomic-scale properties from first principles in physics, chemistry and materials science. Continuing development of new methods is necessary for accurate predictions of new classes of materials and properties, and for connecting to nano- and mesoscale properties using coarse-grained theories. JDFTx is a fully-featured open-source electronic DFT software designed specifically to facilitate rapid development of new theories, models and algorithms. Using an algebraic formulation as an abstraction layer, compact C++11 code automatically performs well on diverse hardware including GPUs (Graphics Processing Units). This code hosts the development of joint density-functional theory (JDFT) that combines electronic DFT with classical DFT and continuum models of liquids for first-principles calculations of solvated and electrochemical systems. In addition, the modular nature of the code makes it easy to extend and interface with, facilitating the development of multi-scale toolkits that connect to ab initio calculations, e.g. photo-excited carrier dynamics combining electron and phonon calculations with electromagnetic simulations.
Collapse
Affiliation(s)
- Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180
| | | | - Kathleen A. Schwarz
- National Institute of Standards and Technology, Material Measurement Laboratory, Gaithersburg, MD, 20899
| | - Deniz Gunceler
- Department of Physics, Cornell University, Ithaca, NY 14853
| | - Yalcin Ozhabes
- Department of Physics, Cornell University, Ithaca, NY 14853
| | - T.A. Arias
- Department of Physics, Cornell University, Ithaca, NY 14853
| |
Collapse
|
43
|
Nakajima T, Sawada K. Discovery of Pb-Free Perovskite Solar Cells via High-Throughput Simulation on the K Computer. J Phys Chem Lett 2017; 8:4826-4831. [PMID: 28927268 DOI: 10.1021/acs.jpclett.7b02203] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We performed a systematic high-throughput simulation with density functional theory for 11 025 compositions of hybrid organic-inorganic halide compounds in ABX3 and A2BB'X6 forms, where A is an organic or inorganic component, B/B' is a metal atom, and X is a halogen atom. The computational results were compiled as a materials database. We performed massive computational simulation by using the K computer, which is a massively parallel many-core supercomputer in Japan. By applying the screening procedure to all the compounds in the materials database, we discovered novel candidates for environmentally friendly lead-free perovskite solar cells and propose 51 low-toxic halide single and double perovskites, most of which are newly proposed in this study. The proposed low-toxic halide double perovskites are classified under six families: group-14-group-14, group-13-group-15, group-11-group-11, group-9-group-13, group-11-group-13, and group-11-group-15 double perovskites.
Collapse
Affiliation(s)
- Takahito Nakajima
- Computational Molecular Science Research Team, RIKEN Advanced Institute for Computational Science , 7-1-26 minatojima-minami, Cyuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Keisuke Sawada
- Computational Molecular Science Research Team, RIKEN Advanced Institute for Computational Science , 7-1-26 minatojima-minami, Cyuo-ku, Kobe, Hyogo 650-0047, Japan
| |
Collapse
|
44
|
|
45
|
Erba A. Self-consistent hybrid functionals for solids: a fully-automated implementation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:314001. [PMID: 28594334 DOI: 10.1088/1361-648x/aa7823] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A fully-automated algorithm for the determination of the system-specific optimal fraction of exact exchange in self-consistent hybrid functionals of the density-functional-theory is illustrated, as implemented into the public Crystal program. The exchange fraction of this new class of functionals is self-consistently updated proportionally to the inverse of the dielectric response of the system within an iterative procedure (Skone et al 2014 Phys. Rev. B 89, 195112). Each iteration of the present scheme, in turn, implies convergence of a self-consistent-field (SCF) and a coupled-perturbed-Hartree-Fock/Kohn-Sham (CPHF/KS) procedure. The present implementation, beside improving the user-friendliness of self-consistent hybrids, exploits the unperturbed and electric-field perturbed density matrices from previous iterations as guesses for subsequent SCF and CPHF/KS iterations, which is documented to reduce the overall computational cost of the whole process by a factor of 2.
Collapse
Affiliation(s)
- A Erba
- Dipartimento di Chimica, Università di Torino, Via Giuria 5, 10125 Torino, Italy
| |
Collapse
|
46
|
Chan B, Kawashima Y, Hirao K. Correlation functional in screened-exchange density functional theory procedures. J Comput Chem 2017; 38:2307-2315. [DOI: 10.1002/jcc.24882] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/27/2017] [Accepted: 06/23/2017] [Indexed: 02/01/2023]
Affiliation(s)
- Bun Chan
- Graduate School of Engineering; Nagasaki University; Bunkyo 1-14, Nagasaki-shi Nagasaki 852-8521 Japan
| | - Yukio Kawashima
- RIKEN Advanced Institute for Computational Science; 7-1-26 Minatojima-minami-machi, Chuo-ku, Kobe Hyogo 650-0047 Japan
| | - Kimihiko Hirao
- RIKEN Advanced Institute for Computational Science; 7-1-26 Minatojima-minami-machi, Chuo-ku, Kobe Hyogo 650-0047 Japan
| |
Collapse
|
47
|
Beuerle M, Kussmann J, Ochsenfeld C. Screening methods for linear-scaling short-range hybrid calculations on CPU and GPU architectures. J Chem Phys 2017; 146:144108. [DOI: 10.1063/1.4978476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthias Beuerle
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstrasse 7, D-81377 München, Germany and Center for Integrated Protein Science (CIPSM) at the Department of Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, D-81377 München, Germany
| | - Jörg Kussmann
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstrasse 7, D-81377 München, Germany and Center for Integrated Protein Science (CIPSM) at the Department of Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, D-81377 München, Germany
| | - Christian Ochsenfeld
- Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstrasse 7, D-81377 München, Germany and Center for Integrated Protein Science (CIPSM) at the Department of Chemistry, University of Munich (LMU), Butenandtstrasse 5-13, D-81377 München, Germany
| |
Collapse
|
48
|
Viñes F, Lamiel-García O, Chul Ko K, Yong Lee J, Illas F. Systematic study of the effect of HSE functional internal parameters on the electronic structure and band gap of a representative set of metal oxides. J Comput Chem 2017; 38:781-789. [DOI: 10.1002/jcc.24744] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/22/2016] [Accepted: 01/10/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Francesc Viñes
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; c/Martí i Franquès 1 Barcelona 08028 Spain
| | - Oriol Lamiel-García
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; c/Martí i Franquès 1 Barcelona 08028 Spain
| | - Kyoung Chul Ko
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; c/Martí i Franquès 1 Barcelona 08028 Spain
- Department of Chemistry; Sungkyunkwan University; Suwon 16419 Korea
| | - Jin Yong Lee
- Department of Chemistry; Sungkyunkwan University; Suwon 16419 Korea
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB); Universitat de Barcelona; c/Martí i Franquès 1 Barcelona 08028 Spain
| |
Collapse
|
49
|
Abstract
We compare the ability of four popular hybrid density functionals (B3LYP, B3PW91, HSE, and PBE0) for predicting band gaps of semiconductors and insulators over a large benchmark set using a consistent methodology. We observe no significant statistical difference in their overall performance, although the screened hybrid HSE is more accurate for typical semiconductors. HSE can improve its accuracy for large band gap materials-without affecting that of semiconductors-by including a larger portion of Hartree-Fock exchange in its short-range. Given that screened hybrids are computationally much less expensive than their global counterparts, we conclude that they are a better option for the black box prediction of band gaps.
Collapse
Affiliation(s)
- Alejandro J Garza
- Department of Chemistry and ‡Department of Physics and Astronomy, Rice University , Houston, Texas 77251-1892, United States
| | - Gustavo E Scuseria
- Department of Chemistry and ‡Department of Physics and Astronomy, Rice University , Houston, Texas 77251-1892, United States
| |
Collapse
|
50
|
Yu HS, Li SL, Truhlar DG. Perspective: Kohn-Sham density functional theory descending a staircase. J Chem Phys 2016; 145:130901. [DOI: 10.1063/1.4963168] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Haoyu S. Yu
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
| | - Shaohong L. Li
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
| | - Donald G. Truhlar
- Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
| |
Collapse
|