Relativistic effects on the optical response of InSb by time-dependent density-functional theory

Kootstra, F.; Boeij, P.L. de; Aissa, H.; Snijders, J.G.

doi:10.1063/1.1334615

Cited by 12 publications

(18 citation statements)

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“…Note that this redshift is compatible but smaller than the error in the calculated band gaps, in line with previous findings. 17,32 Our results indicate that for ZnTe and CdTe the relative position of the s-like conduction band with respect to the p-like top valence band is too low, whereas the dispersion of the bands is well described. The spectra of HgTe reflect the strong impact of relativity on the electronic structure: in particular, the relativistic absorption spectra show the onset at ប = 0 eV, while the nonrelativistic one shows the onset at a finite frequency and is quite different from the experiments.…”

Section: Nonmetals: Ii-vi Zinc-blende-type Znte Cdte Hgtementioning

confidence: 70%

“…A similar formalism that treats scalar relativistic effects only has previously been combined with the time-dependent currentdensity functional formulation of the linear response of solids to a macroscopic electric field. [17][18][19] Although the scalar relativistic effects account for the most important relativistic contributions in the spectra, 19,20 some characteristic features were still missing due to the neglect of spin-orbit coupling. For example, in the group VB and VIB bcc transition metals the treatment of spin-orbit coupling is expected to yield a finite gap in the interband contribution to the absorption spectra, while in the scalar relativistic calculations the absorption remains finite even down to ប = 0 eV.…”

Section: Introductionmentioning

confidence: 99%

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Relativistic two-component formulation of time-dependent current-density functional theory: Application to the linear response of solids

Boeij

2007

The Journal of Chemical Physics

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In this paper we derive the relativistic two-component formulation of time-dependent current-density-functional theory. To arrive at a two-component current-density formulation we apply a Foldy-Wouthuysen-type transformation to the time-dependent four-component Dirac-Kohn-Sham equations of relativistic density-functional theory. The two-component Hamiltonian is obtained as a regular expansion which is gauge invariant at each order of approximation, and to zeroth order it represents the time-dependent version of the relativistic zeroth order regular Hamiltonian obtained by van Lenthe et al., for the ground state [J. Chem. Phys.99, 4597 (1993)]. The corresponding zeroth order regular expression for the density is unchanged, whereas the current-density operator now comprises a paramagnetic, a diamagnetic, and a spin contribution, similar to the Gordon decomposition of the Dirac four current. The zeroth order current density is directly related to the mean velocity corresponding to the zeroth order Hamiltonian. These density and current density operators satisfy the continuity equation. This zeroth order approximation is therefore consistent and physically realistic. By combining this formalism with the formulation of the linear response of solids within time-dependent current-density functional theory [Romaniello and de Boeij, Phys. Rev. B71, 155108 (2005)], we derive a method that can treat orbital and spin contributions to the response in a unified way. The effect of spin-orbit coupling can now be taken into account. As first test we apply the method to calculate the relativistic effects in the linear response of several metals and nonmetals to a macroscopic electric field. Treatment of spin-orbit coupling yields visible changes in the spectra: a smooth onset of the interband transitions in the absorption spectrum of Au, a sharp onset with peak at about 0.46eV in the absorption spectrum of W, and a low-frequency doublet structure in the absorption spectra of ZnTe, CdTe, and HgTe in agreement with experimental results.

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Section: Nonmetals: Ii-vi Zinc-blende-type Znte Cdte Hgtementioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Relativistic two-component formulation of time-dependent current-density functional theory: Application to the linear response of solids

Boeij

2007

The Journal of Chemical Physics

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“…15,16 They followed the description of van Lenthe and co-workers 17,18 and Philipsen et al 19 by using the zeroth-order regular approximation ͑ZORA͒. Scalar-relativistic effects are then considered by using the ground-state scalar ZORA equation,…”

Section: ͑3͒mentioning

confidence: 99%

Optical properties of bcc transition metals in the range0–40eV

2006

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Optical properties of bcc transition metals in the range 0-40 eV Romaniello, P.; de Boeij, PL; Carbone, F; van der Marel, D Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. We present a systematic analysis of the optical properties of bcc transition metals in the groups VB: V, Nb, and Ta, and VIB: paramagnetic Cr, Mo, and W. For this we use our formulation of time-dependent currentdensity-functional theory for the linear response of metals. The calculated dielectric and electron energy-loss functions are compared with our ellipsometry measurements and with data reported in literature, showing an overall good agreement. The experimental data of the dielectric functions presented by Nestell and Christy and by Weaver et al. differ mostly in the low-frequency region. However, we found that their reflectivity data are in very good agreement up to about 3 eV. We attribute this apparent discrepancy to the Drude-like extrapolation model used by Weaver et al. in the Kramers-Kronig procedure to extract the optical constants from their reflectivity data. Our experiments are in good agreement with Nestell and Christy's data. The calculated absorption spectra show some deviations from the experiments, in particular in the 3d metals. We assign the spectra in terms of transitions between pairs of bands and we analyze which parts of the Brillouin zone are mainly involved in the absorption. Our results suggest that the blueshift of some spectral features in our calculations can be attributed mainly to the incorrect description of the virtual d bands by the approximations used for the ground state exchange-correlation functional. These virtual bands are too weakly bound by the local density and generalized gradient approximations, in particular in the 3d metals. We calculate separately the inter-and intraband contributions to the absorption and we show using a k · p analysis that, within the scalar-relativistic approximation, interband transitions contribute to the absorption already at frequencies well below 0.5 eV. This finding makes questionable the Drude-like behavior normally assumed in the experimental analysis of the linear response. We find that the combination of the Drude model in which we use the calculated plasma frequency and an optimized relaxation time, and the calculated interband response can well describe the experimental spectra. The electron energy-loss spectra are very well reproduced by our calculations showing in each metal a dominant plasmon peak at about 22-24 eV, well above the corresponding Drude-like freeelectron plasma frequency, and additional features in the range 10-15 eV. We show that the renormalization of the plasma frequency is due to the interplay between inte...

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“…The density matrix at equilibrium can be written as the Fermi function of the Hamiltonian matrix as below [11]:…”

Section: Theorymentioning

confidence: 99%

“…Which H is Hamiltonian, μ is Fermi energy and I is the identity matrix of same size as H. It can be shown; the charge density is given by diagonal elements of density matrix [11]:…”

Section: Theorymentioning

confidence: 99%

The Magnetic Field Effects on Radially Symmetric Core-Shell-Shell Structure

Simchi¹,

Smaeilzadeh²,

Saani³

2011

OPJ

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In this paper, we modeled a core/shell/shell structure with cylindrical Schrodinger-Poisson coupled equation when a magnetic field is (and is not) applied along its axis. We showed the electron density is peaked near the outer surface of the channel when the magnetic field is applied. Therefore one may make a nano-device which its electrons move only on its outer surface. Also we applied a gate voltage to the device and showed a higher threshold voltage (to turn on the device) is necessary when a magnetic field is applied. This is because of the increase in the lowest energy level similar to the size quantization. i.e a device with longer channel looks like a device with shorter channel if it is placed in a magnetic field parallel to its axis.

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Relativistic effects on the optical response of InSb by time-dependent density-functional theory

Abstract: Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Cited by 12 publications

References 17 publications

Relativistic two-component formulation of time-dependent current-density functional theory: Application to the linear response of solids

Relativistic two-component formulation of time-dependent current-density functional theory: Application to the linear response of solids

Optical properties of bcc transition metals in the range0–40eV

The Magnetic Field Effects on Radially Symmetric Core-Shell-Shell Structure

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