Electronic Structure: Basic Theory and Practical Methods, by Richard M. Martin

Probert, Matt

doi:10.1080/00107514.2010.509989

Cited by 188 publications

(298 citation statements)

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“…In addition, many-body ( G 0 W 0 ) calculations including exciton binding effect (by solving the Bethe–Salpeter equation, BSE) are adopted with a kinetic cutoff energy of 600 eV and a total number of 360 bands invoked. We find that our many-body results agree well with previous reports. − In order to simulate photon excitation, we adopt the constrained-DFT (c-DFT) approach which solves the Kohn–Sham equation with fixed electron and hole excitation concentrations near band edges. This approach has been applied to mimic the photoexcited states in various systems, such as photon emission in semiconductors, magnetic phase transition, and phase transformations in perovskites and transition-metal dichalcogenide monolayers…”

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confidence: 88%

Photoinduced Rippling of Two-Dimensional Hexagonal Nitride Monolayers

et al. 2022

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Inducing structural changes and deformation using noninvasive methods, such as ultrafast laser technology, is an attractive route to multiple optomechanical and optoelectronic applications. Here, we show how photon excitation could accumulate inplane stress and induce long-wavelength ripples in two-dimensional (2D) materials. Numerical results based on first-principles calculations and a continuum model predict that long-range nanoscale rippling could emerge under photon excitation in hexagonal nitride single atomic sheets. The photosoftened transverse acoustic mode dominates the out-of-plane distortion of the sheet, and the resultant rippling pattern strongly depends on the boundary condition. We reveal that the wavelength and height of the ripple scale as I −1/3 and I 1/6 , respectively, where I is the incident light energy flux. Our findings based on multiscale theory and simulations elucidate the interplay between carrier excitation, phonon dispersion, and long-range mechanical deformations, which could find potential usage in flexible electronics and electromechanical devices.

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supporting

confidence: 88%

Photoinduced Rippling of Two-Dimensional Hexagonal Nitride Monolayers

et al. 2022

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“…In this work, we use the latter procedure to compute U k mn because this method allows one to straightforwardly construct WFs from any band structure method without the need to modify the underlying SCF algorithm. One can think of a crystal in the real space as a giant molecule subjected to the Bornvon Karman boundary conditions, 45 defined as a computational supercell, composed of as many unit cells as the numbers of k-points used to sample the FBZ. Figure 1 shows such a computational supercell for a square crystal in a two-dimensional space.…”

Section: Dual Representation For Periodic Systemsmentioning

confidence: 99%

Periodic Electronic Structure Calculations with the Density Matrix Embedding Theory

Pham

Hermes

Gagliardi

2019

J. Chem. Theory Comput.

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We developed a periodic version of density matrix embedding theory, DMET, with which it is possible to perform electronic structure calculations on periodic systems, and compute the band structure of solid-state materials. Electron correlation can be captured by means of a local impurity model using various wave function methods, like, for example, full configuration interaction, coupled cluster and multiconfigurational methods. The method is able to describe not only the ground-state energy but also the quasiparticle band picture via the real-momentum space implementation. We investigate the performance of periodic DMET in describing the ground-state energy as well as the electronic band structure for one-dimensional solids. Our results show that DMET is in good agreement with other many-body techniques at a cheaper computational cost. We anticipate that periodic DMET can be a promising first principle method for strongly correlated materials. arXiv:1909.08783v2 [cond-mat.str-el]An accurate and affordable numerical method for strongly correlated electrons in solid-state materials remains one of the most exciting but challenging topics in computational chemistry and material science. 1 This is crucially important because electron correlation governs many exotic phenomena in condensed phases, such as metal-insulator transition, unconventional superconductivity, and magnetism. 2-4 For decades, Kohn-Sham density functional theory (KS-DFT) 5,6 has been the most successful method for solid-state materials due to its simplicity and predictive capability for many cases. 7,8 While formally exact, the practical application of KS-DFT using approximate exchange-correlation (XC) functional is unable to provide a good description for strong electronic interaction. This is often attributed to the single-determinant nature of the KS fictitious system. 9 Even within the weak correlation regime, the exact KS orbitals energy gap or simply KS band gap (≡ LU M O − HOM O , with LU M O and HOM O are the lowest unoccupied and highest occupied molecular orbital energy, respectively) cannot be interpreted as the fundamental band gap (≡ IP − EA with IP and EA are ionization potential and electron affinity, respectively) owing to the derivative discontinuity of the exchange-correlation energy (IP − EA = LU M O − HOM O + ∆, with ∆ is the derivative discontinuity). 10 Strictly speaking, KS-DFT band structure is unphysical as pointed out in the early work by Perdew and Levy, 10 Sham and Schluter, 11 and recently byBaerends. 12 This argument also applies to approximate functionals based on the local density approximation (LDA) or generalized gradient approximation (GGA). LDA/GGA usually underestimate the fundamental band gap of solids. (For solids the fundamental band gap is very close to the optical band gap which is related to the first excitation; 12 the distinction is not necessary here and we use the term 'band gap' to refer to the fundamental band gap throughout this paper.) This so-called band gap problem 13 makes KS-DFT less appealing ...

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“…As expected, the GGA lattice parameters are slightly overestimated (B0.1%). 55 The GGA computed bandgap for BaCeCuS 3 is found to be 1.15 eV which is underestimated as compared to the experimental values of B1.8 eV. The computed bandgap value is along the expected trend since, in general, the semi-local approximations such as GGA are known to systematically underestimate the bandgaps by as much as B50% as compared to the experiments.…”

Section: àmentioning

confidence: 76%