Collective excitations in the accumulation layer of InAs(110): Nonlocal response theory

Yu, Hong; Hermanson, John C.

doi:10.1103/physrevb.40.11851

Cited by 31 publications

(10 citation statements)

References 27 publications

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“…This evolution can be observed by HREELS. Among various possible intrasubband and intersubband excitations, intrasubband excitations in the lowest subband play a major role, 26 and these excitations are composed of electronic transitions in the lowest subband around the Fermi level. As shown clearly in Sec.…”

Section: Discussionmentioning

confidence: 99%

“…For simplicity of calculation, we describe the charged surface by a uniform distribution of surface charges that extends right outside and along each background surface. 10,[22][23][24][25][26][27][28][29]31,32,35 We assume the charge neutrality of the whole system that is composed of the carrier system, the positive background, and the surface-charge distribution.…”

Section: Theorymentioning

confidence: 99%

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Evolution of electron states at a narrow-gap semiconductor surface in an accumulation-layer formation process

2002

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Adsorption on a doped semiconductor surface often induces a gradual formation of a carrier-accumulation layer at the surface. Taking full account of a nonparabolic ͑NP͒ conduction-band dispersion of a narrow-gap semiconductor, such as InAs and InSb, we investigate the evolution of electron states at the surface in an accumulation-layer formation process. The NP conduction band is incorporated into a local-density-functional formalism. We compare the calculated results for the NP dispersion with those for the parabolic ͑P͒ dispersion with the band-edge effective mass. With increase in the accumulated carrier density N S , the accumulated carriers for the NP conduction band start to be more localized in closer vicinity to the surface than those for the P one. As the bottoms of a few lowest subbands drop below the Fermi level one after another with increase in N S , the nonparabolicity begins to have a great influence on the dispersion and the bottom of each of these subbands, particularly on those of the lowest subband. The present work provides a numerical basis for making a quantitative examination of surface electronic excitations in the accumulation-layer formation process.

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Section: Discussionmentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Evolution of electron states at a narrow-gap semiconductor surface in an accumulation-layer formation process

2002

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“…21 This explains why a distinct phonon peak is not observed on the ͑111͒ surfaces even at the lowest electron energy ͑Fig. 2͒.…”

Section: B 2d Electron Plasmon Modesmentioning

confidence: 98%

Surface-plasmon modes in Zn-doped InAs(001) and (111)

1997

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We have investigated the plasmon modes present at the ͑001͒ and ͑111͒ surfaces of heavily doped p-type InAs, using high-resolution electron-energy-loss spectroscopy ͑HREELS͒ together with dielectric theory simulations. Two-dimensional electron plasmon modes are supported in the inversion layer close to the polar surfaces, however, these modes appear in the experimental HREEL spectra only as a broadening of the elastic peak due to their low energy. Deeper into the bulk, the hole plasma is characterized by light-and heavy-hole components supporting both optical and acoustic plasmon modes. Observation of the optical hole plasmon in HREELS allows the hole density profile to be estimated using dielectric theory simulations, which employ two plasma oscillators incorporating spatial dispersion to model the two-component hole plasma. It is found that native spatial dispersion cannot account for the pronounced experimental plasmon dispersion observed following argon-ion bombardment and annealing of the samples. This procedure is shown to cause rapid diffusion of the zinc acceptors into the near-surface region, resulting in large, highly nonuniform hole concentrations over the length scales probed by HREELS. The acoustic hole plasmon mode, which cannot normally be observed in specular HREELS, is discussed in terms of a two-oscillator, two-layer model. It is shown that acoustic modes do not contribute to specular HREEL spectra even in the limit of highly nonuniform charge distributions.

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“…We describe these carriers in surface states by a uniform distribution of surface charges that extends just outside and along the background surface. [31][32][33][34][35][36] We calculate the dynamical response of the surface with or without a depletion layer to a periodic and oscillatory external potential that has surface-parallel wave vector Q and angular frequency . This dynamical response involves the coupling of surface excitations of carriers with surface polar phonons.…”

Section: Theorymentioning

confidence: 99%

“…Another scheme is a complete Hartree calculation of a carrier system in a semiconductor film. [33][34][35] In this scheme, the effective potential is calculated numerically without parametrizing it.…”

Section: Introductionmentioning

confidence: 99%

Evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process

Inaoka

2001

Phys. Rev. B

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We investigate the evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process. The elementary excitations analyzed are two coupled plasmon-phonon modes and a surface optical-phonon mode involving screening charges. Surface excitations of free carriers are calculated by taking account of the Coulomb interaction between carriers, the dynamical exchange-correlation effect, and the coupling with surface polar phonons, on the basis of thermal-equilibrium states calculated self-consistently by the local-density approximation. We focus our attention on the coupling character and the spatial structure of each surface-excitation mode, as well as the energy dispersion and the energy-loss intensity involved in the excitation. The induced charge-density distribution in the excitation mode is composed of a carrier component due to carrier density fluctuation, a phonon component arising from longitudinal polarphonon polarization, and two on-surface components originating from the termination of the polar phonon and background polarization at the surface. The coupling character is elucidated by the phase relation and the amplitude ratio among these induced charge components. The spatial structure is visualized by the contour map of the induced charge-density distribution. We follow the variation in the coupling character and the spatial structure in the depletion-layer formation process. Our analysis gives a clear explanation of the variation in each of the three loss peaks in the electron energy-loss spectrum.

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Collective excitations in the accumulation layer of InAs(110): Nonlocal response theory

Cited by 31 publications

References 27 publications

Evolution of electron states at a narrow-gap semiconductor surface in an accumulation-layer formation process

Evolution of electron states at a narrow-gap semiconductor surface in an accumulation-layer formation process

Surface-plasmon modes in Zn-doped InAs(001) and (111)

Evolution of elementary excitations at a doped polar semiconductor surface in a depletion-layer formation process

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