Comparative Study of Absorption Spectra of V2+, Cr3+, and Mn4+in α-Al2O3Based on First-Principles Configuration–Interaction Calculations

Novita, Mega; Ogasawara, Kazuyoshi

doi:10.1143/jpsj.81.104709

Cited by 31 publications

(12 citation statements)

References 18 publications

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“…The AlO bond lengths in bulk α ‐Al 2 O 3 can be classified into two groups, i.e., the group with the bond length of 1.85 and 1.96 Å, respectively. Regarding

{Cr}_{Al}^{0}

, the CrO bond lengths can be again classified into two groups: 1.93 and 1.98 Å, which agree well with previous calculated bond lengths of 1.93 and 1.99 Å [ 40 ] and with the measurement of 1.92 and 2.01 Å. [ 38 ] Compared with those in bulk α ‐Al 2 O 3 , the CrO bond lengths are elongated by ≈1.16% and 4.65%.…”

Section: Resultssupporting

confidence: 89%

“…Al , the Cr─O bond lengths can be again classified into two groups: 1.93 and 1.98 Å, which agree well with previous calculated bond lengths of 1.93 and 1.99 Å [40] and with the measurement of 1.92 and 2.01 Å. [38] Compared with those in bulk α-Al 2 O 3 , the Cr─O bond lengths are elongated by %1.16% and 4.65%.…”

Section: Defect Structure and Formation Energysupporting

confidence: 88%

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First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby

Na-Phattalung

Limpijumnong

T‐Thienprasert

2020

Physica Status Solidi (b)

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Using first‐principles calculations within hybrid functional, chromium defects in α‐Al2O3 are investigated, which are believed to be the cause of red color in ruby. It is found that the chromium substitution for aluminum (CrAl) defect has low formation energy under both Al‐ and O‐rich growth conditions, whereas the formation energy of the Cr substitution for O (CrO) defect is much higher, except under p‐type and Al‐rich growth conditions. In addition, Cr interstitial (Cri) also has low formation energy under p‐type and Al‐rich conditions, and its formation energy is somewhat lower than that of CrO. However, natural sapphire is an insulator indicating that the Fermi‐level position should be around the midgap. This confirms that Cr is likely to substitute for Al atom. By exploring the optical properties of the CrAl defect to identify the origin of red color in ruby, the absorption energies associated with the transition of CrAl1+ to CrAl0 and CrAl1− to CrAl0 are 2.12 and 2.73 eV, respectively. The former and latter can be assigned to the observed U and Y bands, respectively, which are believed to be the origin of red color in ruby. Further, it is suggested that the emission lines R, R', and B are associated with other defects or other mechanisms.

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“…The AlO bond lengths in bulk α ‐Al 2 O 3 can be classified into two groups, i.e., the group with the bond length of 1.85 and 1.96 Å, respectively. Regarding

{Cr}_{Al}^{0}

Section: Resultssupporting

confidence: 89%

Section: Defect Structure and Formation Energysupporting

confidence: 88%

First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby

Na-Phattalung

Limpijumnong

T‐Thienprasert

2020

Physica Status Solidi (b)

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“…Duan et al calculated the whole multiplet structure of ruby while their method could not be applicable to the calculation of the emission spectra [18]. Ogasawara et al developed a hybrid method combining density functional theory (DFT) and the CI to obtain multiplet structures [19][20][21]. However, such methods based on CI have some problems to treat TM in solids.…”

Section: Introductionmentioning

confidence: 99%

Construction of model Hamiltonians for the transition-metal impurities via the QSGW method

Saito

Suzuki

Satō

et al. 2023

Preprint

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We show a method to construct model Hamiltonians for describing multiplet excitations of transition-metal impurities. Here we treat systems of a transition metal substituting Al in α-Al2O3. Based on the results of quasiparticle self-consistent GW (QSGW) calculations for the systems, we construct the model Hamiltonian of 3d orbitals. We determine not only the crystal field parameters but also the parameters of effective interactions based on the theoretical correspondence between QSGW calculations and the model Hamiltonian, and investigate systematic change of these parameters. Finally, we discuss the structures of multiplet excitations calculated from these parameters.

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“…[8] Transition metal ions (e.g., V 2+ , Cr 3+ , Co 2+ , Ni 2+ , Fe 5+ , and Cu 2+ ) mostly process broad NIR-emitting property and relatively strong absorption due to spin-allowed 3d-3d transitions. [9,10] In particular, Cr 3+ ion has been thought to be an ideal NIR emitter in virtue of its tunable emission and wide absorption from ultraviolet (UV) A to red region, which directly depends on its crystal-field strength (CFS, D q /B). [11][12][13] Recently, Cr 3+ activated NIR-emitting phosphor materials have become a research hotspot worldwide.…”

Section: Introductionmentioning

confidence: 99%

High‐Performance NIR Emission in Chromium‐Doped Garnet Phosphors Enabled by Structure and Excitation Regulation

Li,

Zhu,

et al. 2023

Laser & Photonics Reviews

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The burgeoning phosphor‐converted near‐infrared light‐emitting diodes (pc‐NIR LEDs) have important applications in special illumination and spectroscopy analysis. However, the development of efficient NIR‐emitting phosphors with high performance is still a challenge. In this work, a chemical unit co‐substitution strategy is proposed to realize the excitation transition regulation and successfully achieve high‐performance NIR luminescence in Ca3‐yNayMg1‐ySb2‐xAl2+yO12: xCr3+ (0 ≤ x ≤ 0.05, 0 ≤ y ≤ 1) garnet‐type solid solution phosphors. Through the excitation transition modulation from the 4A2 ground state to the 4T1(4P) and 4T1(4F) excitation state, the excitation intensity at the blue light region is largely enhanced by 25.6 times. Moreover, the NIR‐emitting efficiency and thermal stability are improved, with the optimal luminescence internal quantum efficiency of 90.6% and thermal stability of 97%@423 K, without any flux‐assisted sintering or reduction atmosphere protection. The structure regulation induced small Stokes shift, weak electron‐phonon coupling effect, and decreased non‐radiative transition are responsible for the excellent NIR‐emitting performance. Finally, the NIR pc‐LED is fabricated with photoelectric efficiencies of 18.7%@100 mA and NIR output powers of 63 mW@100 mA, presenting potential applications in nondestructive internal defect detection, veins imaging, and night vision surveillance.

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Comparative Study of Absorption Spectra of V²⁺, Cr³⁺, and Mn⁴⁺in α-Al₂O₃Based on First-Principles Configuration–Interaction Calculations

Cited by 31 publications

References 18 publications

First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby

First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby

Construction of model Hamiltonians for the transition-metal impurities via the QSGW method

High‐Performance NIR Emission in Chromium‐Doped Garnet Phosphors Enabled by Structure and Excitation Regulation

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Comparative Study of Absorption Spectra of V2+, Cr3+, and Mn4+in α-Al2O3Based on First-Principles Configuration–Interaction Calculations

Cited by 31 publications

References 18 publications

First‐Principles Study of Chromium Defects inα‐Al2O3: The Origin of Red Color in Ruby

First‐Principles Study of Chromium Defects inα‐Al2O3: The Origin of Red Color in Ruby

Construction of model Hamiltonians for the transition-metal impurities via the QSGW method

High‐Performance NIR Emission in Chromium‐Doped Garnet Phosphors Enabled by Structure and Excitation Regulation

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Comparative Study of Absorption Spectra of V²⁺, Cr³⁺, and Mn⁴⁺in α-Al₂O₃Based on First-Principles Configuration–Interaction Calculations

First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby

First‐Principles Study of Chromium Defects inα‐Al₂O₃: The Origin of Red Color in Ruby