Pub Date : 2024-05-08DOI: 10.1088/2516-1075/ad48ec
V. Blum, Ryoji Asahi, Jochen Autschbach, Christoph Bannwarth, G. Bihlmayer, S. Blügel, Lori A. Burns, T. D. Crawford, William Dawson, W. D. de Jong, C. Draxl, Claudia Filippi, Luigi Genovese, P. Giannozzi, N. Govind, Sharon Hammes-Schiffer, Jeff R. Hammond, B. Hourahine, Anubhav Jain, Yosuke Kanai, P. R. Kent, A. H. Larsen, S. Lehtola, Xiaosong Li, Roland Lindh, Satoshi Maeda, N. Makri, Jonathan Moussa, T. Nakajima, Jessica A. Nash, Micael J. T. Oliveira, Pansy D. Patel, Giovanni Pizzi, Geoffrey Pourtois, Benjamin P. Pritchard, E. Rabani, M. Reiher, L. Reining, Xinguo Ren, Mariana Rossi, H. B. Schlegel, N. Seriani, L. Slipchenko, Alexander Thom, Edward F. Valeev, Benoit Van Troeye, Lucas Visscher, V. Vlček, Hans-Joachim Werner, David B. Williams-Young, Theresa Windus
Contents 1. Introduction- Methods and software for electronic structure based simulations of chemistry and materials 2. Density Functional Theory: Formalism and Current Directions 3. Density functional methods - implementation, challenges, successes 4. Green’s function based many-body perturbation theory 5. Wave-function theory approaches – explicit approaches to electron correlation 6. Quantum Monte Carlo and stochastic electronic structure methods 7. Heavy element relativity, spin-orbit physics, and magnetism 8. Semiempirical methods 9. Simulating Nuclear Dynamics with Quantum Effects 10. Real-Time Propagation in Electronic Structure Theory 11. Spectroscopy 12. Tools for exploring potential energy surfaces 13. Managing complex computational workflows 14. Current and Future Computer Architectures 15. Electronic structure software engineering 16. Education and Training in Electronic Structure Theory: Navigating an Evolving Landscape 17. Electronic structure theory facing industry and realistic modeling of experiments 18. List of Acronyms
{"title":"Roadmap on methods and software for electronic structure based simulations in chemistry and materials","authors":"V. Blum, Ryoji Asahi, Jochen Autschbach, Christoph Bannwarth, G. Bihlmayer, S. Blügel, Lori A. Burns, T. D. Crawford, William Dawson, W. D. de Jong, C. Draxl, Claudia Filippi, Luigi Genovese, P. Giannozzi, N. Govind, Sharon Hammes-Schiffer, Jeff R. Hammond, B. Hourahine, Anubhav Jain, Yosuke Kanai, P. R. Kent, A. H. Larsen, S. Lehtola, Xiaosong Li, Roland Lindh, Satoshi Maeda, N. Makri, Jonathan Moussa, T. Nakajima, Jessica A. Nash, Micael J. T. Oliveira, Pansy D. Patel, Giovanni Pizzi, Geoffrey Pourtois, Benjamin P. Pritchard, E. Rabani, M. Reiher, L. Reining, Xinguo Ren, Mariana Rossi, H. B. Schlegel, N. Seriani, L. Slipchenko, Alexander Thom, Edward F. Valeev, Benoit Van Troeye, Lucas Visscher, V. Vlček, Hans-Joachim Werner, David B. Williams-Young, Theresa Windus","doi":"10.1088/2516-1075/ad48ec","DOIUrl":"https://doi.org/10.1088/2516-1075/ad48ec","url":null,"abstract":"\u0000 Contents 1. Introduction- Methods and software for electronic structure based simulations of chemistry and materials 2. Density Functional Theory: Formalism and Current Directions 3. Density functional methods - implementation, challenges, successes 4. Green’s function based many-body perturbation theory 5. Wave-function theory approaches – explicit approaches to electron correlation 6. Quantum Monte Carlo and stochastic electronic structure methods 7. Heavy element relativity, spin-orbit physics, and magnetism 8. Semiempirical methods 9. Simulating Nuclear Dynamics with Quantum Effects 10. Real-Time Propagation in Electronic Structure Theory 11. Spectroscopy 12. Tools for exploring potential energy surfaces 13. Managing complex computational workflows 14. Current and Future Computer Architectures 15. Electronic structure software engineering 16. Education and Training in Electronic Structure Theory: Navigating an Evolving Landscape 17. Electronic structure theory facing industry and realistic modeling of experiments 18. List of Acronyms","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140998398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-02DOI: 10.1088/2516-1075/ad46b5
Arul Raj Natarajan, B. Pujari, G. Vaitheeswaran, V. Kanchana
Exploring novel two-dimensional materials (2D) for electrode and electrochemical storage applications stands as a pivotal pursuit in advancing renewable energy technologies. While recent research has predominantly focused on anode materials, cathode materials have received comparatively lesser attention. This study delves into the potential cathode applications of the novel two-dimensional material NbS2Cl2 using density functional theory. Fundamental properties, encompassing electronic and thermodynamic attributes, were scrutinized to comprehend the material’s characteristics. Our investigation extended to examining the adsorption and diffusion properties of these electrode materials. Comprehensive calculations of mechanical and thermodynamic properties reaffirmed the stability of this system. Upon adsorption of Li/Na atoms, the conducting nature emerged, evident through charge density difference and projected density of states (PDOS). Our findings notably reveal minimal diffusion barriers of 1.5 eV and 0.35 eV for Li and Na atoms. Moreover, the observed open circuit voltages (OCV) for adsorbed Li and Na ions were 4.69 V and 2.62 V, respectively. The calculated theoretical capacity for adsorbed Li-ion on 2D-NbS2Cl2 is 400 mAh/g, while for Na-ion adsorption, it is 353 mAh/g, awaiting validation through future experimental verifications.
探索新型二维材料（2D）在电极和电化学储能方面的应用，是推动可再生能源技术发展的一项关键任务。近期的研究主要集中在阳极材料上，而阴极材料则相对较少受到关注。本研究利用密度泛函理论深入研究了新型二维材料 NbS2Cl2 的潜在阴极应用。我们仔细研究了包括电子和热力学属性在内的基本特性，以了解这种材料的特点。我们的研究还扩展到这些电极材料的吸附和扩散特性。机械和热力学特性的综合计算再次证实了该系统的稳定性。通过电荷密度差和投影态密度（PDOS）可以看出，在吸附 Li/Na 原子后，导电性能显现出来。我们的研究结果表明，锂原子和瑙原子的最小扩散势垒分别为 1.5 eV 和 0.35 eV。此外，吸附的锂离子和钠离子的开路电压（OCV）分别为 4.69 V 和 2.62 V。计算得出的二维-NbS2Cl2 上吸附锂离子的理论容量为 400 mAh/g，而吸附 Na 离子的理论容量为 353 mAh/g，有待今后的实验验证。
{"title":"Investigation of cathode properties of two-dimensional NbS2Cl2 for Li and Na-ion batteries using density functional theory","authors":"Arul Raj Natarajan, B. Pujari, G. Vaitheeswaran, V. Kanchana","doi":"10.1088/2516-1075/ad46b5","DOIUrl":"https://doi.org/10.1088/2516-1075/ad46b5","url":null,"abstract":"\u0000 Exploring novel two-dimensional materials (2D) for electrode and electrochemical storage applications stands as a pivotal pursuit in advancing renewable energy technologies. While recent research has predominantly focused on anode materials, cathode materials have received comparatively lesser attention. This study delves into the potential cathode applications of the novel two-dimensional material NbS2Cl2 using density functional theory. Fundamental properties, encompassing electronic and thermodynamic attributes, were scrutinized to comprehend the material’s characteristics. Our investigation extended to examining the adsorption and diffusion properties of these electrode materials. Comprehensive calculations of mechanical and thermodynamic properties reaffirmed the stability of this system. Upon adsorption of Li/Na atoms, the conducting nature emerged, evident through charge density difference and projected density of states (PDOS). Our findings notably reveal minimal diffusion barriers of 1.5 eV and 0.35 eV for Li and Na atoms. Moreover, the observed open circuit voltages (OCV) for adsorbed Li and Na ions were 4.69 V and 2.62 V, respectively. The calculated theoretical capacity for adsorbed Li-ion on 2D-NbS2Cl2 is 400 mAh/g, while for Na-ion adsorption, it is 353 mAh/g, awaiting validation through future experimental verifications.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141022255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The point defects induced in crystalline solids during the growth process unintentionally or doped intentionally after the growth process significantly modify their properties. The intentionally controlled doping of point defects in crystalline solids has been widely used to tune their properties. In this paper, we investigate the effect of vacancy and substitutional point defects on the electronic and thermoelectric properties of pentagonal PdX 2 (X= Se, S) monolayers using the density functional theory (DFT) and semi-classical Boltzmann transport theory. We find that the point defects in pentagonal PdX 2 (X= Se, S) monolayers modify their electronic structures. The contributions of d orbitals of Pd atoms and p orbitals of Se/S atoms are significantly affected due to the presence of point defects in the lattice. The defect states are appeared within the band gap region which effectively reduces the band gap of the monolayer. These defect states could be helpful in tuning the electrical and optical properties of the monolayer. The transport calculations show that the presence of the point defects in the lattice reduces the thermoelectric performance of PdX 2 monolayers. Both the Seebeck coefficient and electrical conductivity show deteriorated behaviour under the influence of point defects in the lattice. Thus, the influence of these defects must be carefully taken into account while fabricating these materials for practical applications.
晶体固体在生长过程中无意诱发的点缺陷或在生长过程后有意掺杂的点缺陷都会极大地改变其特性。在晶体固体中有意控制地掺杂点缺陷已被广泛用于调节其性质。本文利用密度泛函理论（DFT）和半经典波尔兹曼输运理论，研究了空位点缺陷和取代点缺陷对五边形 PdX 2（X= Se，S）单层的电子和热电性能的影响。我们发现五边形 PdX 2 (X= Se, S) 单层中的点缺陷改变了它们的电子结构。由于晶格中存在点缺陷，钯原子的 d 轨道和 Se/S 原子的 p 轨道的贡献受到了很大影响。缺陷态出现在带隙区域内，从而有效地减小了单层的带隙。这些缺陷态有助于调整单层的电学和光学特性。传输计算表明，晶格中点缺陷的存在降低了 PdX 2 单层的热电性能。在晶格中点缺陷的影响下，塞贝克系数和电导率都出现了恶化。因此，在为实际应用制造这些材料时，必须仔细考虑这些缺陷的影响。
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Pub Date : 2024-04-08DOI: 10.1088/2516-1075/ad38f8
William A Wheeler, Kevin G Kleiner, Lucas K Wagner
Variational Monte Carlo methods have recently been applied to the calculation of excited states; however, it is still an open question what objective function is most effective. A promising approach is to optimize excited states using a penalty to minimize overlap with lower eigenstates, which has the drawback that states must be computed one at a time. We derive a general framework for constructing objective functions with minima at the the lowest N eigenstates of a many-body Hamiltonian. The objective function uses a weighted average of the energies and an overlap penalty, which must satisfy several conditions. We show this objective function has a minimum at the exact eigenstates for a finite penalty, and provide a few strategies to minimize the objective function. The method is demonstrated using ab initio variational Monte Carlo to calculate the degenerate first excited state of a CO molecule.
变异蒙特卡洛方法最近被应用于激发态的计算；然而，什么目标函数最有效仍是一个悬而未决的问题。一种很有前途的方法是利用惩罚来优化激发态，以尽量减少与低特征态的重叠，但这种方法的缺点是必须一次计算一个态。我们推导出一个通用框架，用于构建在多体哈密顿最低 N 个特征状态处具有最小值的目标函数。目标函数使用能量的加权平均值和重叠惩罚，必须满足几个条件。我们证明了在罚金有限的情况下，该目标函数在精确特征点处具有最小值，并提供了几种最小化目标函数的策略。我们利用 ab initio 变分蒙特卡洛计算一氧化碳分子的退化第一激发态来演示该方法。
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Pub Date : 2024-04-02DOI: 10.1088/2516-1075/ad31ca
Susi Lehtola
Recent developments in fully numerical methods promise interesting opportunities for new, compact atomic orbital (AO) basis sets that maximize the overlap to fully numerical reference wave functions, following the pioneering work of Richardson and coworkers from the early 1960s. Motivated by this technique, we suggest a way to visualize the importance of AO basis functions employing fully numerical wave functions computed at the complete basis set limit: the importance of a normalized AO basis function |α⟩ centered on some nucleus can be visualized by projecting |α⟩ on the set of numerically represented occupied orbitals |ψi⟩ as I0(α)=∑i⟨α|ψi⟩⟨ψi|α⟩. Choosing α to be a continuous parameter describing the AO basis, such as the exponent of a Gaussian-type orbital or Slater-type orbital basis function, one is then able to visualize the importance of various functions. The proposed visuali
{"title":"Importance profiles. Visualization of atomic basis set requirements","authors":"Susi Lehtola","doi":"10.1088/2516-1075/ad31ca","DOIUrl":"https://doi.org/10.1088/2516-1075/ad31ca","url":null,"abstract":"Recent developments in fully numerical methods promise interesting opportunities for new, compact atomic orbital (AO) basis sets that maximize the overlap to fully numerical reference wave functions, following the pioneering work of Richardson and coworkers from the early 1960s. Motivated by this technique, we suggest a way to visualize the importance of AO basis functions employing fully numerical wave functions computed at the complete basis set limit: the importance of a normalized AO basis function <inline-formula>\u0000<tex-math><?CDATA $|alpharangle$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mo stretchy=\"false\">|</mml:mo><mml:mi>α</mml:mi><mml:mo fence=\"false\" stretchy=\"false\">⟩</mml:mo></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"estad31caieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> centered on some nucleus can be visualized by projecting <inline-formula>\u0000<tex-math><?CDATA $|alpharangle$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mo stretchy=\"false\">|</mml:mo><mml:mi>α</mml:mi><mml:mo fence=\"false\" stretchy=\"false\">⟩</mml:mo></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"estad31caieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> on the set of numerically represented occupied orbitals <inline-formula>\u0000<tex-math><?CDATA $|psi_{i}rangle$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mo stretchy=\"false\">|</mml:mo><mml:msub><mml:mi>ψ</mml:mi><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:msub><mml:mo fence=\"false\" stretchy=\"false\">⟩</mml:mo></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"estad31caieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> as <inline-formula>\u0000<tex-math><?CDATA $I_{0}(alpha) = sum_{i}langlealpha|psi_{i}ranglelanglepsi_{i}|alpharangle$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>I</mml:mi><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo stretchy=\"false\">(</mml:mo><mml:mi>α</mml:mi><mml:mo stretchy=\"false\">)</mml:mo><mml:mo>=</mml:mo><mml:munder><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:munder><mml:mo fence=\"false\" stretchy=\"false\">⟨</mml:mo><mml:mi>α</mml:mi><mml:mrow><mml:mo stretchy=\"false\">|</mml:mo></mml:mrow><mml:msub><mml:mi>ψ</mml:mi><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:msub><mml:mo fence=\"false\" stretchy=\"false\">⟩</mml:mo><mml:mo fence=\"false\" stretchy=\"false\">⟨</mml:mo><mml:msub><mml:mi>ψ</mml:mi><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:msub><mml:mrow><mml:mo stretchy=\"false\">|</mml:mo></mml:mrow><mml:mi>α</mml:mi><mml:mo fence=\"false\" stretchy=\"false\">⟩</mml:mo></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"estad31caieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. Choosing <italic toggle=\"yes\">α</italic> to be a continuous parameter describing the AO basis, such as the exponent of a Gaussian-type orbital or Slater-type orbital basis function, one is then able to visualize the importance of various functions. The proposed visuali","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140584593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-28DOI: 10.1088/2516-1075/ad3592
Mario Motta, William Kirby, Ieva Liepuoniute, Kevin J Sung, Jeffrey Cohn, Antonio Mezzacapo, Katherine Klymko, Nam Nguyen, Nobuyuki Yoshioka, Julia E Rice
Quantum subspace methods (QSMs) are a class of quantum computing algorithms where the time-independent Schrödinger equation for a quantum system is projected onto a subspace of the underlying Hilbert space. This projection transforms the Schrödinger equation into an eigenvalue problem determined by measurements carried out on a quantum device. The eigenvalue problem is then solved on a classical computer, yielding approximations to ground- and excited-state energies and wavefunctions. QSMs are examples of hybrid quantum–classical methods, where a quantum device supported by classical computational resources is employed to tackle a problem. QSMs are rapidly gaining traction as a strategy to simulate electronic wavefunctions on quantum computers, and thus their design, development, and application is a key research field at the interface between quantum computation and electronic structure (ES). In this review, we provide a self-contained introduction to QSMs, with emphasis on their application to the ES of molecules. We present the theoretical foundations and applications of QSMs, and we discuss their implementation on quantum hardware, illustrating the impact of noise on their performance.
{"title":"Subspace methods for electronic structure simulations on quantum computers","authors":"Mario Motta, William Kirby, Ieva Liepuoniute, Kevin J Sung, Jeffrey Cohn, Antonio Mezzacapo, Katherine Klymko, Nam Nguyen, Nobuyuki Yoshioka, Julia E Rice","doi":"10.1088/2516-1075/ad3592","DOIUrl":"https://doi.org/10.1088/2516-1075/ad3592","url":null,"abstract":"Quantum subspace methods (QSMs) are a class of quantum computing algorithms where the time-independent Schrödinger equation for a quantum system is projected onto a subspace of the underlying Hilbert space. This projection transforms the Schrödinger equation into an eigenvalue problem determined by measurements carried out on a quantum device. The eigenvalue problem is then solved on a classical computer, yielding approximations to ground- and excited-state energies and wavefunctions. QSMs are examples of hybrid quantum–classical methods, where a quantum device supported by classical computational resources is employed to tackle a problem. QSMs are rapidly gaining traction as a strategy to simulate electronic wavefunctions on quantum computers, and thus their design, development, and application is a key research field at the interface between quantum computation and electronic structure (ES). In this review, we provide a self-contained introduction to QSMs, with emphasis on their application to the ES of molecules. We present the theoretical foundations and applications of QSMs, and we discuss their implementation on quantum hardware, illustrating the impact of noise on their performance.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140584849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-18DOI: 10.1088/2516-1075/ad3124
Daniel Mejia-Rodriguez
The GW approximation has become an important tool for predicting charged excitations of isolated molecules and condensed systems. Its popularity can be attributed to many factors, including a favorable scaling and relatively good accuracy. In practical applications, the GW is often performed as a one-shot perturbation known as G0W0. Unfortunately, G0W0 suffers from a strong starting point dependence and is often not as accurate as one would need. Self-consistent GW methodologies alleviate these problems but come with a marked increase in computational cost. In this manuscript, we propose the use of an estimate of the exchange-correlation derivative discontinuity to provide a remarkably good starting point for G0W0 calculations, yielding ionization potentials and electron affinities with eigenvalue self-consistent GW quality at no additional cost. We assess the quality of the resulting methodology with the GW100 benchmark set and compare its advantages over other similar methods.
{"title":"Exploiting a derivative discontinuity estimate for accurate G0W0 ionization potentials and electron affinities","authors":"Daniel Mejia-Rodriguez","doi":"10.1088/2516-1075/ad3124","DOIUrl":"https://doi.org/10.1088/2516-1075/ad3124","url":null,"abstract":"The <italic toggle=\"yes\">GW</italic> approximation has become an important tool for predicting charged excitations of isolated molecules and condensed systems. Its popularity can be attributed to many factors, including a favorable scaling and relatively good accuracy. In practical applications, the <italic toggle=\"yes\">GW</italic> is often performed as a one-shot perturbation known as <inline-formula>\u0000<tex-math><?CDATA $G_0W_0$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>G</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>W</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad3124ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. Unfortunately, <inline-formula>\u0000<tex-math><?CDATA $G_0W_0$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>G</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>W</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad3124ieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> suffers from a strong starting point dependence and is often not as accurate as one would need. Self-consistent <italic toggle=\"yes\">GW</italic> methodologies alleviate these problems but come with a marked increase in computational cost. In this manuscript, we propose the use of an estimate of the exchange-correlation derivative discontinuity to provide a remarkably good starting point for <inline-formula>\u0000<tex-math><?CDATA $G_0W_0$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>G</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>W</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad3124ieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> calculations, yielding ionization potentials and electron affinities with eigenvalue self-consistent <italic toggle=\"yes\">GW</italic> quality at no additional cost. We assess the quality of the resulting methodology with the <italic toggle=\"yes\">GW</italic>100 benchmark set and compare its advantages over other similar methods.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-15DOI: 10.1088/2516-1075/ad2eb0
David M Ceperley, Scott Jensen, Yubo Yang, Hongwei Niu, Carlo Pierleoni, Markus Holzmann
Quantum Monte Carlo (QMC) can play a very important role in generating accurate data needed for constructing potential energy surfaces. We argue that QMC has advantages in terms of a smaller systematic bias and an ability to cover phase space more completely. The stochastic noise can ease the training of the machine learning model. We discuss how stochastic errors affect the generation of effective models by analyzing the errors within a linear least squares procedure, finding that there is an advantage to having many relatively imprecise data points for constructing models. We then analyze the effect of noise on a model of many-body silicon finding that noise in some situations improves the resulting model. We then study the effect of QMC noise on two machine learning models of dense hydrogen used in a recent study of its phase diagram. The noise enables us to estimate the errors in the model. We conclude with a discussion of future research problems.
{"title":"Training models using forces computed by stochastic electronic structure methods","authors":"David M Ceperley, Scott Jensen, Yubo Yang, Hongwei Niu, Carlo Pierleoni, Markus Holzmann","doi":"10.1088/2516-1075/ad2eb0","DOIUrl":"https://doi.org/10.1088/2516-1075/ad2eb0","url":null,"abstract":"Quantum Monte Carlo (QMC) can play a very important role in generating accurate data needed for constructing potential energy surfaces. We argue that QMC has advantages in terms of a smaller systematic bias and an ability to cover phase space more completely. The stochastic noise can ease the training of the machine learning model. We discuss how stochastic errors affect the generation of effective models by analyzing the errors within a linear least squares procedure, finding that there is an advantage to having many relatively imprecise data points for constructing models. We then analyze the effect of noise on a model of many-body silicon finding that noise in some situations improves the resulting model. We then study the effect of QMC noise on two machine learning models of dense hydrogen used in a recent study of its phase diagram. The noise enables us to estimate the errors in the model. We conclude with a discussion of future research problems.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-07DOI: 10.1088/2516-1075/ad29ab
A D N James, M Aichhorn, J Laverock
The last few decades has seen the rapid growth of interest in the bulk perovskite-type transition metal oxides SrVO3 and SrTiO3. The electronic configuration of these perovskites differs by one electron associated to the transition metal species which gives rise to the drastically different electronic properties. Therefore, it is natural to look into how the electronic structure transitions between these bulk structures by using doping. Measurements of the substitutional doped SrTi1−xVxO3 shows an metal–insulator transition (MIT) as a function of doping. By using supercell density functional theory with dynamical mean field theory (DFT+DMFT), we show that the MIT is indeed the result of the combination of local electron correlation effects (Mott physics) within the t2g orbitals and the atomic site configuration of the transition metals which may indicate dependence on site disorder. SrTi1−xVxO3 may be an ideal candidate for benchmarking cutting-edge Mott–Anderson models of real systems. We show that applying an effective external perturbation on SrTi1−x
{"title":"Composition-driven Mott transition within SrTi 1−x V x O3","authors":"A D N James, M Aichhorn, J Laverock","doi":"10.1088/2516-1075/ad29ab","DOIUrl":"https://doi.org/10.1088/2516-1075/ad29ab","url":null,"abstract":"The last few decades has seen the rapid growth of interest in the bulk perovskite-type transition metal oxides SrVO<sub>3</sub> and SrTiO<sub>3</sub>. The electronic configuration of these perovskites differs by one electron associated to the transition metal species which gives rise to the drastically different electronic properties. Therefore, it is natural to look into how the electronic structure transitions between these bulk structures by using doping. Measurements of the substitutional doped SrTi<inline-formula>\u0000<tex-math><?CDATA $_{{1-x}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi> </mml:mi><mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad29abieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>V<inline-formula>\u0000<tex-math><?CDATA $_{{{x}}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi></mml:mi><mml:mrow><mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:mrow></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad29abieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>O<sub>3</sub> shows an metal–insulator transition (MIT) as a function of doping. By using supercell density functional theory with dynamical mean field theory (DFT+DMFT), we show that the MIT is indeed the result of the combination of local electron correlation effects (Mott physics) within the <inline-formula>\u0000<tex-math><?CDATA $t_{{mathrm{2g}}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>t</mml:mi><mml:mrow><mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mi mathvariant=\"normal\">g</mml:mi></mml:mrow></mml:mrow></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad29abieqn5.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> orbitals and the atomic site configuration of the transition metals which may indicate dependence on site disorder. SrTi<inline-formula>\u0000<tex-math><?CDATA $_{{1-x}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi> </mml:mi><mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad29abieqn6.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>V<inline-formula>\u0000<tex-math><?CDATA $_{{{x}}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi></mml:mi><mml:mrow><mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:mrow></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"estad29abieqn7.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>O<sub>3</sub> may be an ideal candidate for benchmarking cutting-edge Mott–Anderson models of real systems. We show that applying an effective external perturbation on SrTi<inline-formula>\u0000<tex-math><?CDATA $_{{1-x}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi> </mml:mi><mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:mrow></mml","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-02DOI: 10.1088/2516-1075/ad2f5b
Danilo Gómez-Ríos, Santiago Perez-Walton, Francisco López-Giraldo, J. Peralta, William Espinoza
Compounds based on chalcogen elements are widely studied currently due to their many interesting applications for electronic devices. The sodium-based dichalcogenide (NaNbS$_2$) is a fascinating material with storage and conversion energy applications. In this paper, we conduct a first-principles investigation of the structural and thermodynamic stability and electronic properties of this material. We analyze a total of four structures to find the ground state using a fourth-order Birch-Murnaghan equation of state: the $alpha$ and $eta$ related to the A-phase and the $zeta_{1}$ and $zeta_{2}$ related to the B-phase. We carefully address the exchange-correlation effects using the semi- local GGA-PBEsol targeted for solids. To analyze the electronic structure with higher accuracy, we implement the quasi-particle G${textup{o}}$W${textup{o}}$ approximation. textcolor{red}{Our results for the fourth-order Birch-Murnaghan equation show that the most thermodynamically stable phase at zero temperature is $alpha$.} To provide experimentalists insights about the possible routes to grow these materials, we calculated the convex hull of the $alpha$-model and $zeta_{1}$-model, finding that both are energetically stable. Finally, the calculated band gap with quasiparticle corrections for the $alpha$-model is 1.03 eV, which suggests possible applications of this material as a bottom cell in modern solar cells.
{"title":"Sodium-based di-chalcogenide: A promising material for tandem solar cells","authors":"Danilo Gómez-Ríos, Santiago Perez-Walton, Francisco López-Giraldo, J. Peralta, William Espinoza","doi":"10.1088/2516-1075/ad2f5b","DOIUrl":"https://doi.org/10.1088/2516-1075/ad2f5b","url":null,"abstract":"\u0000 Compounds based on chalcogen elements are widely studied currently due to their many interesting applications for electronic devices. The sodium-based dichalcogenide (NaNbS$_2$) is a fascinating material with storage and conversion energy applications. In this paper, we conduct a first-principles investigation of the structural and thermodynamic stability and electronic properties of this material. We analyze a total of four structures to find the ground state using a fourth-order Birch-Murnaghan equation of state: the $alpha$ and $eta$ related to the A-phase and the $zeta_{1}$ and $zeta_{2}$ related to the B-phase. We carefully address the exchange-correlation effects using the semi- local GGA-PBEsol targeted for solids. To analyze the electronic structure with higher accuracy, we implement the quasi-particle G${textup{o}}$W${textup{o}}$ approximation. textcolor{red}{Our results for the fourth-order Birch-Murnaghan equation show that the most thermodynamically stable phase at zero temperature is $alpha$.} To provide experimentalists insights about the possible routes to grow these materials, we calculated the convex hull of the $alpha$-model and $zeta_{1}$-model, finding that both are energetically stable. Finally, the calculated band gap with quasiparticle corrections for the $alpha$-model is 1.03 eV, which suggests possible applications of this material as a bottom cell in modern solar cells.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140081418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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