Efficient many-body calculations for two-dimensional materials using exact limits for the screened potential: Band gaps of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="bold">MoS</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>,</mml:mo><mml:mo> </mml:mo><mml:mi>h</mml:mi></mml:math>-BN, and phosphorene

Rasmussen, Filip; Schmidt, Per Simmendefeldt; Winther, Kirsten T.; Thygesen, Kristian Sommer

doi:10.1103/physrevb.94.155406

Cited by 88 publications

(100 citation statements)

References 51 publications

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“…We stress that these are the only two QSHI candidates of the Kane-Mele type we found (in addition to graphene itself which is not included here owing to its vanishing small band gap). tions when predicting topological phases [37], especially for 2D materials where dielectric screening is weak and the dielectric function has a strong spatial dependence [40,41]. AsCuLi 2 .…”

Section: Resultsmentioning

confidence: 99%

Relative Abundance of Z2 Topological Order in Exfoliable Two-Dimensional Insulators

et al. 2019

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Quantum spin Hall insulators are a class of two-dimensional materials with a finite electronic band gap in the bulk and gapless helical edge states. In the presence of time-reversal symmetry, Z2 topological order distinguishes the topological phase from the ordinary insulating one. Some of the phenomena that can be hosted in these materials, from one-dimensional low-dissipation electronic transport to spin filtering, could be very promising for many technological applications in the fields of electronics, spintronics and topological quantum computing. Nevertheless, the rarity of twodimensional materials that can exhibit non-trivial Z2 topological order at room temperature hinders development. Here, we screen a comprehensive database we recently created of 1825 monolayers that can be exfoliated from experimentally known compounds, to search for novel quantum spin Hall insulators. Using density-functional and many-body perturbation theory simulations, we identify 13 monolayers that are candidates for quantum spin Hall insulators, including high-performing materials such as AsCuLi2 and jacutingaite (Pt2HgSe3). We also identify monolayer Pd2HgSe3 as a novel Kane-Mele quantum spin Hall insulator, and compare it with jacutingaite. Such a handful of promising materials are mechanically stable and exhibit Z2 topological order, either unpertubed or driven by a small amount of strain. Such screening highlights a relative abundance of Z2 topological order of around 1%, and provides an optimal set of candidates for experimental efforts. arXiv:1908.08334v1 [cond-mat.mtrl-sci]

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Section: Resultsmentioning

confidence: 99%

Relative Abundance of Z2 Topological Order in Exfoliable Two-Dimensional Insulators

et al. 2019

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“…GW calculations for 2D materials pose additional challenges due to the analytical behavior of the 2D electronic screening, which is different from 3 dimensional (3D) systems, and the need to remove interactions between period images33343536. The rapid change in the 2D dielectric function as requires rather dense k -point sampling even with clever integration techniques3336; the spurious interlayer interaction can be reduced with increasing interlayer distance and with the use of truncated Coulomb potential3334.…”

Section: Resultsmentioning

confidence: 99%

“…The rapid change in the 2D dielectric function as requires rather dense k -point sampling even with clever integration techniques3336; the spurious interlayer interaction can be reduced with increasing interlayer distance and with the use of truncated Coulomb potential3334. Unfortunately, even with these creative methods, fully converged GW calculations for 2D materials remain a serious challenge since the number of conduction bands required in the calculation scales linearly with cell volume.…”

Section: Resultsmentioning

confidence: 99%

Speeding up GW Calculations to Meet the Challenge of Large Scale Quasiparticle Predictions

Gao

Xia

Gao

et al. 2016

Sci Rep

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Although the GW approximation is recognized as one of the most accurate theories for predicting materials excited states properties, scaling up conventional GW calculations for large systems remains a major challenge. We present a powerful and simple-to-implement method that can drastically accelerate fully converged GW calculations for large systems, enabling fast and accurate quasiparticle calculations for complex materials systems. We demonstrate the performance of this new method by presenting the results for ZnO and MgO supercells. A speed-up factor of nearly two orders of magnitude is achieved for a system containing 256 atoms (1024 valence electrons) with a negligibly small numerical error of ±0.03 eV. Finally, we discuss the application of our method to the GW calculations for 2D materials.

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“…3 is the quasiparticle (QP) excitation energy E QP at the fixed geometry R q , which can be calculated accurately using the GW method [16,22,23]. However, GW calculations of quasiparticle energies in 2D materials exhibit serious convergence difficulties [24][25][26] that make the calculations of charged defects that require large supercells extremely challenging.…”

Section: Computationmentioning

confidence: 99%

First-principles engineering of charged defects for two-dimensional quantum technologies

Galatas

Sundararaman

et al. 2017

Phys. Rev. Materials

103

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Charged defects in 2D materials have emerging applications in quantum technologies such as quantum emitters and quantum computation. Advancement of these technologies requires rational design of ideal defect centers, demanding reliable computation methods for quantitatively accurate prediction of defect properties. We present an accurate, parameter-free and efficient procedure to evaluate quasiparticle defect states and thermodynamic charge transition levels of defects in 2D materials. Importantly, we solve critical issues that stem from the strongly anisotropic screening in 2D materials, that have so far precluded accurate prediction of charge transition levels in these materials. Using this procedure, we investigate various defects in monolayer hexagonal boron nitride (h-BN) for their charge transition levels, stable spin states and optical excitations. We identify CBVN (nitrogen vacancy adjacent to carbon substitution of boron) to be the most promising defect candidate for scalable quantum bit and emitter applications.Two-dimensional (2D) materials such as graphene, hexagonal Boron Nitride (h-BN) and transition metal dichalcogenides exhibit a wide range of remarkable properties at atomic-scale layer thicknesses, holds promise for both conventional and new optoelectronic functionality at drastically reduced dimensions [1][2][3][4][5]. It is well established that point defects play a central role in the properties of bulk 3D semiconductors but their corresponding role in 2D materials is not yet well understood. In particular, the weak screening environment surrounding the defect charge distribution and the strong confinement of wavefunctions due to the atomic-scale thickness could lead to vastly different behavior compared to conventional semiconductors.Defects in 2D materials such as h-BN show promise as polarized and ultra-bright single-photon emitters at room temperature, with potentially better scalability than the long-studied nitrogen-vacancy center(NV) in diamond [6][7][8] for emerging applications in nanophotonics and quantum information.[9] Progress beyond initial experimental demonstration of promising properties requires rational design and development of quantum defects in 2D materials that exhibit high emission rate, long coherence time, single photon purity and stability. Specifically, the promising defects should have the following properties: defect levels should be deep (far from band edges) to avoid resonance with the bulk band edges and thereby exhibit long coherence time; [10,11] opticallyaddressable spin conserving excitations facilitate exploiting spin-selective decays in high-spin defect states, similar to the NV center in diamond; [12][13][14] anisotropic polarization of the defect states in combination with quantum bits could provide a pathway to quantum optical FIG. 1. Left: CBVN defect energy levels in monolayer BN with spin up (up arrow) and spin down (down arrow) channels respectively. The black filled arrows represent occupied states and unfilled arrows represent unoccupied states. ...

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Efficient many-body calculations for two-dimensional materials using exact limits for the screened potential: Band gaps ofMoS2, h-BN, and phosphorene

Cited by 88 publications

References 51 publications

Relative Abundance of Z2 Topological Order in Exfoliable Two-Dimensional Insulators

Relative Abundance of Z2 Topological Order in Exfoliable Two-Dimensional Insulators

Speeding up GW Calculations to Meet the Challenge of Large Scale Quasiparticle Predictions

First-principles engineering of charged defects for two-dimensional quantum technologies

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