Accurate defect levels obtained from the HSE06 range-separated hybrid functional

Deák, Péter; Aradi, Bálint; Frauenheim, Thomas; Janzén, Erik; Gali, Ádám

doi:10.1103/physrevb.81.153203

Cited by 322 publications

(191 citation statements)

References 44 publications

Supporting

Mentioning

178

Contrasting

Unclassified

Order By: Relevance

“…The results are shown in Table VI, and once again we find a good agreement between calculated and experimental values. The discrepancy between the calculated and measured ZPL energies for each configuration is within 0.1 eV that is expected from HSE06 hybrid density functional method 36 . However, the calculated differences between the ZPL energies of the defect configurations are technically converged within few meV, in terms of the parameters of plane wave supercell DFT method.…”

Section: Magneto-optical Properties Of Nv Center In Sicmentioning

confidence: 53%

Characterization and formation of NV centers in 3C, 4H , and 6H SiC: An ab initio study

et al. 2017

View full text Add to dashboard Cite

Fluorescent paramagnetic defects in solids have become attractive systems for quantum information processing in the recent years. One of the leading contenders is the negatively charged nitrogen-vacancy defect in diamond with visible emission but alternative solution in technologically mature host is an immediate quest for many applications in this field. It has been recently found that various polytypes of silicon carbide (SiC), that are standard semiconductors with wafer scale technology, can host nitrogen-vacancy defect (NV) that could be an alternative qubit candidate with emission in the near infrared region. However, it is much less known about this defect than its counterpart in diamond. The inequivalent sites within a polytype and the polytype variations offer a family of NV defects. However, there is an insufficient knowledge on the magneto-optical properties of these configurations. Here we carry out density functional theory calculations, in order to characterize the numer ous forms of NV defects in the most common polytypes of SiC including 3C, 4H and 6H, and we also provide new experimental data in 4H SiC. Our calculations mediate the identification of individual NV qubits in SiC polytypes. In addition, we discuss the formation of NV defects in SiC with providing detailed ionization energies of NV defect in SiC which reveals the critical optical excitation energies for ionizing this qubits in SiC. Our calculations unravel the challenges to produce NV defects in SiC with a desirable spin bath.

show abstract

Section: Magneto-optical Properties Of Nv Center In Sicmentioning

confidence: 53%

Characterization and formation of NV centers in 3C, 4H , and 6H SiC: An ab initio study

et al. 2017

View full text Add to dashboard Cite

show abstract

“…A variety of approaches have been proposed, 22 including applications of Hubbard-U-like terms (LDA + U or GGA + U) to cation d states 40 or to multiple orbital channels, 41 the Slater-Janak transition model, 42,43 modified pseudopotentials, 44 Becke-Johnson type functionals, 45,46 combining DFT with quasiparticle calculations, 35,36 and hybrid functionals. [47][48][49][50][51][52][53][54][55][56] Hybrid functionals have emerged as the current method of choice, 22 applicable to a wide variety of systems including defects in Si, 47,48 GaAs, 51 diamond, 48 and oxides. 49,50 In the following, unless specified otherwise, we assume that hybrid functional results are obtained with HSE.…”

Section: Introductionmentioning

confidence: 99%

Computationally predicted energies and properties of defects in GaN

2017

View full text Add to dashboard Cite

Recent developments in theoretical techniques have significantly improved the predictive power of density-functional-based calculations. In this review, we discuss how such advancements have enabled improved understanding of native point defects in GaN. We review the methodologies for the calculation of point defects, and discuss how techniques for overcoming the band-gap problem of density functional theory affect native defect calculations. In particular, we examine to what extent calculations performed with semilocal functionals (such as the generalized gradient approximation), combined with correction schemes, can produce accurate results. The properties of vacancy, interstitial, and antisite defects in GaN are described, as well as their interaction with common impurities. We also connect the first-principles results to experimental observations, and discuss how native defects and their complexes impact the performance of nitride devices. Overall, we find that lower-cost functionals, such as the generalized gradient approximation, combined with band-edge correction schemes can produce results that are qualitatively correct. However, important physics may be missed in some important cases, particularly for optical transitions and when carrier localization occurs.

show abstract

“…We apply a plane-wave basis set of 420 eV and standard projector augmented-wave [30] potentials as implemented in the VASP code [31,32]. For ZPL and hyperfine tensor calculations we use the Heyd-Scuseria-Ernzerhof (HSE06) [33,34] hybrid exchange-correlation functional that has already demonstrated its predictive power for optical [35,36] and hyperfine properties [37]. In the zero-field-splitting calculations we use the PerdewBurke-Ernzerhof (PBE) [38] functional that provides accurate results for defects in wide band gap semiconductors [39].…”

mentioning

confidence: 99%

Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide

et al. 2017

Self Cite

View full text Add to dashboard Cite

The identification of a microscopic configuration of point defects acting as quantum bits is a key step in the advance of quantum information processing and sensing. Among the numerous candidates, silicon-vacancy related centers in silicon carbide (SiC) have shown remarkable properties owing to their particular spin-3/2 ground and excited states. Although, these centers were observed decades ago, two competing models, the isolated negatively charged silicon vacancy and the complex of negatively charged silicon vacancy and neutral carbon vacancy [Phys. Rev. Lett. 115, 247602 (2015)], are still argued as an origin. By means of high-precision first-principles calculations and high-resolution electron spin resonance measurements, we here unambiguously identify the Si-vacancy related qubits in hexagonal SiC as isolated negatively charged silicon vacancies. Moreover, we identify the Si-vacancy qubit configurations that provide room-temperature optical readout. DOI: 10.1103/PhysRevB.96.161114 Point defects in solids acting as quantum bits (qubits) are a highly promising platform for quantum information processing (QIP) and nanoscale sensor applications where typically their electron spin provides the functional quantum states. There are qubits that have long electron spin coherence times [1][2][3][4][5], and some of them have been demonstrated to persist up to room temperature [1,4]. These electron spins can be optically initialized and read out [2,6-9], making them very attractive candidates for QIP and related applications [10][11][12]. Among these qubits, silicon-vacancy related defects in hexagonal polytypes of SiC, such as 4H -and 6H -SiC, have shown favorable spin properties [13,14], demonstrated even at a single defect level at room temperature [4]. Two and three different silicon-vacancy related centers were observed in 4H -and 6H -SiC, where the corresponding photoluminescence (PL) lines are denoted as V1 and V2, and V1, V2, and V3, [15,16], respectively. The V2 line in 4H -SiC [4] and the V2 and V3 lines in 6H -SiC [13] are sufficiently strong to observe their corresponding electron spin via optically detected magnetic resonance (ODMR) measurements at room temperature. In particular, it has been demonstrated that the V2 color center in 4H -SiC can be used for magnetometer [17][18][19][20] and nanoscale thermometer [21] applications and as a room-temperature maser [14].Today, it is widely accepted that V1-V3 PL lines and T V1 -T V3 electron paramagnetic resonance (EPR) signals in 4H -and 6H -SiC are related to spin-3/2 negatively charged silicon vacancies [22][23][24][25]. On the other hand, the actual microscopic configuration of these vacancy related centers is still debated. The unanswered question is whether these centers are isolated silicon vacancies [V Si difference between the two models is how the observed finite zero-field splitting (ZFS) of the ground-state spin sublevels is explained. In model I, it is assumed that the C 3v symmetric crystal field, allowing nonzero ZFS [26], is strong enough t...

show abstract

Accurate defect levels obtained from the HSE06 range-separated hybrid functional

Abstract: Fine structure of exciton complexes in high-symmetry quantum dots: Effects of symmetry breaking and symmetry

Cited by 322 publications

References 44 publications

Characterization and formation of NV centers in 3C, 4H , and 6H SiC: An ab initio study

Characterization and formation of NV centers in 3C, 4H , and 6H SiC: An ab initio study

Computationally predicted energies and properties of defects in GaN

Identification of Si-vacancy related room-temperature qubits in 4H silicon carbide

Contact Info

Product

Resources

About