Role of the lattice in the light-induced insulator-to-metal transition in vanadium dioxide

Weber, Cédric; Acharya, Swagata; Cunningham, B.; Grüning, Myrta; Zhang, Liangliang; Zhao, Yuejin; Tan, Yong; Zhang, Yan; Zhang, Cunlin; Li, Kai; Schilfgaarde, Mark van; Shalaby, Mostafa

doi:10.1103/physrevresearch.2.023076

Cited by 15 publications

(11 citation statements)

References 33 publications

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“…As we will show elsewhere [129] the addition of ladders in W seem to dramatically improve on the charge channel even in strongly correlated cases such as CoO. VO 2 is an excellent test bed for optics: it has strong correlations in the monoclinic phase; yet, the conductivity is well described by nonmagnetic QSGW, provided ladders are taken into account [119].…”

Section: Successes Of Qsgwmentioning

confidence: 86%

“…in Cu 2 O, where it was shown that ϵ(ω) calculated from the BSE starting from a QSGW reference described the measured spectrum quite well [178]. Recently Cunningham et al studied optics from BSE using QSGW as reference for a number of systems, and found very good agreement with experiment even in correlated systems such as NiO [116] and the monoclinic phase of VO 2 [119]. However, when spin fluctuations are large and QSGW does not describe the underlying band structure well, as in La 2 CuO 4 (see Section 4.4), the description begins to break down.…”

Section: Optical Response Functions In Questaalmentioning

confidence: 87%

“…There is a similar mismatch for CoO: the gap is overestimated by ∼2 eV in these cases, but not in NiO. Particularly telling is how for VO 2 nonmagnetic QSGW does describe the M1 phase very well when both V-V pairs dimerise [119], but not the M2 phase where only one of them does. (A gap opens up when M2 is calculated antiferromagnetically, but M2 is probably paramagnetic at room temperature.)…”

Section: Limitations Of Qsgwmentioning

confidence: 88%

“…1 in Ref. [83]), even in the strongly correlated M1 phase of VO 2 [118][119][120], where spin fluctuations are not important. It properly narrows the bandwidth of localised d bands and widens it in wide-gap semiconductors [117] and graphene [121].…”

Section: Successes Of Qsgwmentioning

confidence: 92%

“…Kutepov [102] showed that the bandgaps significantly improve, but the improvement extends to a wide range of properties and very diverse kinds of materials systems. See for example, the excellent description of optical conductivity in VO 2 [119].…”

Section: Successes Of Qsgwmentioning

confidence: 99%

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Questaal: A package of electronic structure methods based on the linear muffin-tin orbital technique

Jackson¹

2021

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Section: Successes Of Qsgwmentioning

confidence: 86%

Section: Optical Response Functions In Questaalmentioning

confidence: 87%

Section: Limitations Of Qsgwmentioning

confidence: 88%

Section: Successes Of Qsgwmentioning

confidence: 92%

Section: Successes Of Qsgwmentioning

confidence: 99%

See 3 more Smart Citations

Questaal: A package of electronic structure methods based on the linear muffin-tin orbital technique

Jackson¹

2021

Preprint

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A theory for colors of strongly correlated electronic systems

Acharya,

Pashov,

Weber

et al. 2023

Nat Commun

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Many strongly correlated transition metal insulators are colored, even though they have band gaps much larger than the highest energy photons from the visible light. An adequate explanation for the color requires a theoretical approach able to compute subgap excitons in periodic crystals, reliably and without free parameters—a formidable challenge. The literature often fails to disentangle two important factors: what makes excitons form and what makes them optically bright. We pick two archetypal cases as examples: NiO with green color and MnF2 with pink color, and employ two kinds of ab initio many body Green’s function theories; the first, a perturbative theory based on low-order extensions of the GW approximation, is able to explain the color in NiO, while the same theory is unable to explain why MnF2 is pink. We show its color originates from higher order spin-flip transitions that modify the optical response, which is contained in dynamical mean-field theory (DMFT). We show that symmetry lowering mechanisms may determine how ‘bright’ these excitons are, but they are not fundamental to their existence.

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Real- and momentum-space description of the excitons in bulk and monolayer chromium tri-halides

et al. 2022

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Excitons with large binding energies ~2–3 eV in CrX3 have been characterized as being localized (Frenkel) excitons that emerge from the atomic d − d transitions between the Cr-3d-t2g and eg orbitals. The argument has gathered strength in recent years as the excitons in recently made monolayers are found at almost the same energies as the bulk. The Laporte rule, which restricts such parity forbidden atomic transitions, can relax if a symmetry-breaking mechanism is present. While what can be classified as a purely Frenkel exciton is a matter of definition, we show using an advanced first principles parameter-free approach that these excitons in CrX3, in both its bulk and monolayer variants, have band origin and it is the dp hybridization between Cr and X that primarily acts as the symmetry-breaking mechanism that relaxes the Laporte rule. We show that the character of these excitons is mostly determined by the Cr-d orbital manifold, nevertheless, the fractions of the spectral weight shared with the ligand halogen states increases as the dp hybridization enhances. The hybridization enhances as the halogen atom becomes heavier, bringing the X-p states closer to the Cr-d states in the sequence Cl → Br → I, with an attendant increase in exciton intensity and a decrease in binding energy. By applying a range of different kinds of perturbations that qualitatively mimics the effects originating from the missing vertex in self-energy, we show that moderate changes to the two-particle Hamiltonian that essentially modifies the Cr-d-X-p hybridization, can alter both the intensities and positions of the exciton peaks. A detailed analysis of several deep-lying excitons, with and without strain, elucidates the fact that the exciton is most Frenkel-like in CrCl3 and CrBr3 and acquires mixed Frenkel–Wannier character in CrI3, making the excitons in CrI3 most susceptible to environmental screening and spin–orbit coupling.

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Role of the lattice in the light-induced insulator-to-metal transition in vanadium dioxide

Cited by 15 publications

References 33 publications

Questaal: A package of electronic structure methods based on the linear muffin-tin orbital technique

Questaal: A package of electronic structure methods based on the linear muffin-tin orbital technique

A theory for colors of strongly correlated electronic systems

Real- and momentum-space description of the excitons in bulk and monolayer chromium tri-halides

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