Advanced calculations for defects in materials : electronic structure methods /: electronic structure methods. (2011)

• Record Type: Book
• Further Information: Note: Edited by Audrius Alkauskas ... [et al.].
• Other Names: Alkauskas, Audrius
• Contents: List of Contributors XIII 1 Advances in Electronic Structure Methods for Defects and Impurities in Solids 1 ; Chris G. Van de Walle and Anderson Janotti 1.1 Introduction 1 1.2 Formalism and Computational Approach 3 1.2.1 Defect Formation Energies and Concentrations 3 1.2.2 Transition Levels or Ionization Energies 4 1.2.3 Practical Aspects 5 1.3 The DFT-LDA/GGA Band-Gap Problem and Possible Approaches to Overcome It 6 1.3.1 LDAþU for Materials with Semicore States 6 1.3.2 Hybrid Functionals 9 1.3.3 Many-Body Perturbation Theory in the GW Approximation 12 1.3.4 Modified Pseudopotentials 12 1.4 Summary 13 References 14 2 Accuracy of Quantum Monte Carlo Methods for Point Defects in Solids 17 ; William D. Parker, John W. Wilkins, and Richard G. Hennig 2.1 Introduction 17 2.2 Quantum Monte Carlo Method 18 2.2.1 Controlled Approximations 20 2.2.1.1 Time Step 20 2.2.1.2 Configuration Population 20 2.2.1.3 Basis Set 20 2.2.1.4 Simulation Cell 21 2.2.2 Uncontrolled Approximations 22 2.2.2.1 Fixed-Node Approximation 22 2.2.2.2 Pseudopotential 22 2.2.2.3 Pseudopotential Locality 23 2.3 Review of Previous DMC Defect Calculations 23 2.3.1 Diamond Vacancy 23 2.3.2 MgO Schottky Defect 25 2.3.3 Si Interstitial Defects 25 2.4 Results 25 2.4.1 Time Step 26 2.4.2 Pseudopotential 26 2.4.3 Fixed-Node Approximation 26 2.5 Conclusion 29 References 29 3 Electronic Properties of Interfaces and Defects from Many-body Perturbation Theory: Recent Developments and Applications 33 ; Matteo Giantomassi, Martin Stankovski, Riad Shaltaf, Myrta Grüning, Fabien Bruneval, Patrick Rinke, and Gian-Marco Rignanese 3.1 Introduction 33 3.2 Many-Body Perturbation Theory 34 3.2.1 Hedin.s Equations 34 3.2.2 GW Approximation 36 3.2.3 Beyond the GW Approximation 37 3.3 Practical Implementation of GW and Recent Developments Beyond 38 3.3.1 Perturbative Approach 38 3.3.2 QP Self-Consistent GW 40 3.3.3 Plasmon Pole Models Versus Direct Calculation of the Frequency Integral 41 3.3.4 The Extrapolar Method 44 3.3.4.1 Polarizability with a Limited Number of Empty States 45 3.3.4.2 Self-Energy with a Limited Number of Empty States 46 3.3.5 MBPT in the PAW Framework 46 3.4 QP Corrections to the BOs at Interfaces 48 3.5 QP Corrections for Defects 54 3.6 Conclusions and Prospects 57 References 58 4 Accelerating GW Calculations with Optimal Polarizability Basis 61 ; Paolo Umari, Xiaofeng Qian, Nicola Marzari, Geoffrey Stenuit, Luigi Giacomazzi, and Stefano Baroni 4.1 Introduction 61 4.2 The GW Approximation 62 4.3 The Method: Optimal Polarizability Basis 64 4.4 Implementation and Validation 68 4.4.1 Benzene 69 4.4.2 Bulk Si 70 4.4.3 Vitreous Silica 70 4.5 Example: Point Defects in a-Si3N4 72 4.5.1 Model Generation 72 4.5.2 Model Structure 73 4.5.3 Electronic Structure 74 4.6 Conclusions 77 References 77 5 Calculation of Semiconductor Band Structures and Defects by the Screened Exchange Density Functional 79 ; S. J. Clark and John Robertson 5.1 Introduction 79 5.2 Screened Exchange Functional 80 5.3 Bulk Band Structures and Defects 82 5.3.1 Band Structure of ZnO 83 5.3.2 Defects of ZnO 85 5.3.3 Band Structure of MgO 89 5.3.4 Band Structures of SnO2 and CdO 90 5.3.5 Band Structure and Defects of HfO2 91 5.3.6 BiFeO3 92 5.4 Summary 93 References 94 6 Accurate Treatment of Solids with the HSE Screened Hybrid 97 ; Thomas M. Henderson, Joachim Paier, and Gustavo E. Scuseria 6.1 Introduction and Basics of Density Functional Theory 97 6.2 Band Gaps 100 6.3 Screened Exchange 103 6.4 Applications 104 6.5 Conclusions 107 References 108 7 Defect Levels Through Hybrid Density Functionals: Insights and Applications 111 ; Audrius Alkauskas, Peter Broqvist, and Alfredo Pasquarello 7.1 Introduction 111 7.2 Computational Toolbox 112 7.2.1 Defect Formation Energies and Charge Transition Levels 113 7.2.2 Hybrid Density Functionals 114 7.2.2.1 Integrable Divergence 115 7.3 General Results from Hybrid Functional Calculations 117 7.3.1 Alignment of Bulk Band Structures 118 7.3.2 Alignment of Defect Levels 120 7.3.3 Effect of Alignment on Defect Formation Energies 122 7.3.4 ‘‘The Band-Edge Problem’’ 124 7.4 Hybrid Functionals with Empirically Adjusted Parameters 125 7.5 Representative Case Studies 129 7.5.1 Si Dangling Bond 129 7.5.2 Charge State of O2 During Silicon Oxidation 131 7.6 Conclusion 132 References 134 8 Accurate Gap Levels and Their Role in the Reliability of Other Calculated Defect Properties 139 ; Peter Deák, Adam Gali, Bálint Aradi, and Thomas Frauenheim 8.1 Introduction 139 8.2 Empirical Correction Schemes for the KS Levels 141 8.3 The Role of the Gap Level Positions in the Relative Energies of Various Defect Configurations 143 8.4 Correction of the Total Energy Based on the Corrected Gap Level Positions 146 8.5 Accurate Gap Levels and Total Energy Differences by Screened Hybrid Functionals 148 8.6 Summary 151 References 152 9 LDA þ U and Hybrid Functional Calculations for Defects in ZnO, SnO2, and TiO2 155 ; Anderson Janotti and Chris G. Van de Walle 9.1 Introduction 155 9.2 Methods 156 9.2.1 ZnO 158 9.2.2 SnO2 160 9.2.3 TiO2 161 9.3 Summary 163 References 163 10 Critical Evaluation of the LDA þ U Approach for Band Gap Corrections in Point Defect Calculations: The Oxygen Vacancy in ZnO Case Study 165 ; Adisak Boonchun and Walter R. L. Lambrecht 10.1 Introduction 165 10.2 LDA þ U Basics 166 10.3 LDA þ U Band Structures Compared to GW 168 10.4 Improved LDA þ U Model 170 10.5 Finite Size Corrections 172 10.6 The Alignment Issue 173 10.7 Results for New LDA þ U 174 10.8 Comparison with Other Results 176 10.9 Discussion of Experimental Results 178 10.10 Conclusions 179 References 180 11 Predicting Polaronic Defect States by Means of Generalized Koopmans Density Functional Calculations 183 ; Stephan Lany 11.1 Introduction 183 11.2 The Generalized Koopmans Condition 185 11.3 Adjusting the Koopmans Condition using Parameterized On-Site Functionals 187 11.4 Koopmans Behavior in Hybrid-functionals: The Nitrogen Acceptor in ZnO 189 11.5 The Balance Between Localization and Delocalization 193 11.6 Conclusions 196 References 197 12 SiO2 in Density Functional Theory and Beyond 201 ; L. Martin-Samos, G. Bussi, A. Ruini, E. Molinari, and M.J. Caldas 12.1 Introduction 201 12.2 The Band Gap Problem 202 12.3 Which Gap? 204 12.4 Deep Defect States 207 12.5 Conclusions 209 References 210 13 Overcoming Bipolar Doping Difficulty in Wide Gap Semiconductors 213 ; Su-Huai Wei and Yanfa Yan 13.1 Introduction 213 13.2 Method of Calculation 214 13.3 Symmetry and Occupation of Defec
• Publisher Details: Place of publication not identified : Wiley-VCH
• Publication Date: 2011
• Extent: 1 online resource (402 pages)
• Subjects: 620.1127; Solids -- Mathematical models; Materials -- Testing; Nondestructive testing; Electronic structure -- Mathematical models
• Languages: English
• ISBNs: 9783527638536
• Access Rights: Legal Deposit; Only available on premises controlled by the deposit library and to one user at any one time; The Legal Deposit Libraries (Non-Print Works) Regulations (UK).
• Access Usage: Restricted: Printing from this resource is governed by The Legal Deposit Libraries (Non-Print Works) Regulations (UK) and UK copyright law currently in force.