Optical absorption in GaTe under high pressure

Pellicer‐Porres, J.; Manjón, F. J.; Segura, A.; Muñoz, V.; Power, Ch.; González, J.

doi:10.1103/physrevb.60.8871

Cited by 20 publications

(21 citation statements)

References 35 publications

(39 reference statements)

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“…Both in InSe and In 1−x Ga x Se, the three transitions show nonlinear pressure dependences at low pressures and almost a linear behavior above 2 GPa. A similar nonlinear behavior of the band gaps has also been previously observed in InSe [2,4,6], and also in GaSe [2,3] and E (eV) GaTe [19]. In InSe, the linear pressure coefficients above 2 GPa are 62 meV/GPa, 42 meV/GPa, and −22 meV/GPa for the Z, I 1 , and I 2 transitions, respectively.…”

Section: Pressure Dependence Of the Absorption Edgesupporting

confidence: 83%

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Segura

Manjón

Errandonea

et al. 2003

Physica Status Solidi (b)

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In this paper we review some recent results on the electronic structure of III − VI layered semiconductors and its dependence under pressure, stressing the specific features that differentiate their behaviour from that of tetrahedrally coordinated semiconductors. We will focus on several unexpected results that have led to changes in the image that was currently accepted a few years ago. Intralayer bond angles change under pressure and the layer "thickness" remains virtually constant or increases. As a consequence, models based in intra-and inter-layer deformation potentials fail in explaining the low pressure nonlinearity of the band gap. Numerical-atomic-orbital/density-functional-theory electronic structure calculations allow for an interpretation of the evolution of the absorption edge under pressure. In particular, they show how the structure of the non-degenerated valence band maximum in InSe becomes more complex under pressure leading to a non-conventional direct-to-indirect crossover. The valence band maximum in InSe above 4 GPa exhibits a quite singular feature: a "ring-shaped" constant energy surface and, consequently, a density of states depending on energy as in 2D electronic systems.

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Section: Pressure Dependence Of the Absorption Edgesupporting

confidence: 83%

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Segura

Manjón

Errandonea

et al. 2003

Physica Status Solidi (b)

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“…polarization parallel to the c-axis, in accordance with recent LMTO band structure calculations [23]. An increase of the dielectric constant of GaTe with pressure has also been proposed from the pressure dependence of the exciton Rydberg [24]. On the other hand, an increase of ε ∞⊥ with pressure has been observed in GaS and GaSe [20][21][22].…”

Section: Introductionsupporting

confidence: 83%

Pressure dependence of the refractive index in InSe

Manjón¹,

Vijver

Segura

et al. 2000

Semicond. Sci. Technol.

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In this work we report on the pressure dependence of the refractive index of indium selenide (InSe) for polarization perpendicular to the c-axis (E⊥c). The refractive index dispersion n ⊥ (ω) of InSe has been measured between 0.77 and 1.5 eV for hydrostatic pressures up to 8 GPa and interpreted through a single oscillator Phillips-van Vechten model yielding the electronic refractive index and dielectric function. This model also yields the pressure dependence of the Penn gap in InSe, whose interlayer and intralayer deformation potentials have been obtained and compared with those of the lower energy optical gaps. The possible electronic transitions responsible for the Penn gaps for both polarizations (perpendicular and parallel to the c-axis) in InSe and other III-VI layered materials are also discussed on the basis of recent band structure calculations.

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“…In such a case, the Tauc method can be used, but keeping in mind that the obtained energy is an energy that is always smaller than real bandgap energy, being sensitive to the thickness of the sample . (2) If the bandgap is indirect, the contribution of an indirect transition to the absorption coefficient is much weaker than that of an allowed direct transition and can be measured only when the indirect gap is situated at least 0.2–0.3 eV below the direct one . In such cases, the bandgap energy could be determined assuming for the absorption coefficient a dependence on the square root of the energy: α ( E ) = A E − E gapind , where A is a scaling parameter and E gapind is the bandgap energy of the indirect gap…”

mentioning

confidence: 99%

Accurate Determination of the Bandgap Energy of the Rare-Earth Niobate Series

Garg

Vie

Rodríguez-Hernández

et al. 2023

J. Phys. Chem. Lett.

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We report diffuse reflectivity measurements in InNbO4, ScNbO4, YNbO4, and eight rare-earth niobates. A comparison with established values of the bandgap of InNbO4 and ScNbO4 shows that Tauc plot analysis gives erroneous estimates of the bandgap energy. Conversely, accurate results are obtained considering excitonic contributions using the Elliot–Toyozawa model. The bandgaps are 3.25 eV for CeNbO4, 4.35 eV for LaNbO4, 4.5 eV for YNbO4, and 4.73–4.93 eV for SmNbO4, EuNbO4, GdNbO4, DyNbO4, HoNbO4, and YbNbO4. The fact that the bandgap energy is affected little by the rare-earth substitution from SmNbO4 to YbNbO4 and the fact that they have the largest bandgap are a consequence of the fact that the band structure near the Fermi level originates mainly from Nb 4d and O 2p orbitals. YNbO4, CeVO4, and LaNbO4 have smaller bandgaps because of the contribution from rare-earth atom 4d, 5d, or 4f orbitals to the states near the Fermi level.

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Optical absorption in GaTe under high pressure

Cited by 20 publications

References 35 publications

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Pressure dependence of the refractive index in InSe

Accurate Determination of the Bandgap Energy of the Rare-Earth Niobate Series

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