Photoemission Properties of Simple Metals

Koyama, R. Y.; Smith, N. V.

doi:10.1103/physrevb.2.3049

Cited by 104 publications

(11 citation statements)

References 19 publications

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“…35 The sp bands relevant for our observed transitions are well described by a nearly-free-electron ͑NFE͒ model taking into account two orthogonalized plane waves ͑OPW͒. 36 We show the initial and final sp-band states near the ⌫-L line calculated using this approximation in Fig. 4.…”

Section: A Dispersionmentioning

confidence: 79%

Angle-dependent study of a direct optical transition in thespbands of Ag(111) by one- and two-photon photoemission

et al. 2007

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We have measured angle-dependent photoemission spectra for one-photon and two-photon excitation from Ag͑111͒. The observed dispersion of the sp-band transition of Ag͑111͒ can be reproduced using a nearly-freeelectron model for the initial and final states involved. The observed dispersion agrees with the known band structure. We illustrate how the strong refraction of low-energy electrons becomes a limiting factor to obtain quantitative band-structure information. Conversely, low-energy electrons of a well-defined direct optical interband transition can provide a sensitive probe of the inner potential. We observe asymmetric two-photon photoelectron intensity distributions with respect to detection along the surface normal. These intensity distributions can be well described by a phenomenological model which employs the Fresnel equations to calculate the electric field components of the incident radiation inside the sample. Very good agreement is found using tabulated optical constants and a momentum matrix element, which is oriented along the surface normal. In contrast, the observed intensity distribution for one-photon photoemission from Ag͑111͒ does not fit the simple Fresnel model. We interpret this as the influence of surface photoemission. By comparison to Cu͑001͒, we show that the expected intensity distributions of the Fresnel model for one-photon photoemission and twophoton photoemission are valid for an orientation of the momentum matrix element along the surface normal if the influence of additional effects like surface photoemission can be neglected.

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Section: A Dispersionmentioning

confidence: 79%

Angle-dependent study of a direct optical transition in thespbands of Ag(111) by one- and two-photon photoemission

et al. 2007

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“…This picture allows the description of IPE by using the welldeveloped model of electron photoemission into vacuum (the external photoemission effect) [22,31], even though the replacement of vacuum by another solid ensues nonnegligible effects, some of which will be discussed later. The most successful descriptions of both external and internal electron photoemission processes are based on phenomenological model [40][41][42] considering this quantum phenomenon as a sequence of three relatively independent stages: (1) photoexcitation of a carrier inside a solid, (2) transport of the photoexcited carriers towards the emitting surface (or interface), and (3) escape of the carrier from the surface by surmounting the potential barrier. The well appreciated advantage of this model consists in providing a simple analytical scheme, which can be directly applied to the analysis of experimental results.…”

Section: Basics Of Internal Photoemission Spectroscopymentioning

confidence: 99%

Electron Band Alignment at Interfaces of Semiconductors with Insulating Oxides: An Internal Photoemission Study

Afanasʼev

2014

Advances in Condensed Matter Physics

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Evolution of the electron energy band alignment at interfaces between different semiconductors and wide-gap oxide insulators is examined using the internal photoemission spectroscopy, which is based on observations of optically-induced electron (or hole) transitions across the semiconductor/insulator barrier. Interfaces of various semiconductors ranging from the conventional silicon to the high-mobility Ge-based (Ge,Si1-xGex,Ge1-xSnx) andAIIIBVgroup (GaAs,InxGa1-xAs, InAs, GaP, InP, GaSb, InSb) materials were studied revealing several general trends in the evolution of band offsets. It is found that in the oxides of metals with cation radii larger than≈0.7 Å, the oxide valence band top remains nearly at the same energy (±0.2 eV) irrespective of the cation sort. Using this result, it becomes possible to predict the interface band alignment between oxides and semiconductors as well as between dissimilar insulating oxides on the basis of the oxide bandgap width which are also affected by crystallization. By contrast, oxides of light elements, for example, Be, Mg, Al, Si, and Sc exhibit significant shifts of the valence band top. General trends in band lineup variations caused by a change in the composition of semiconductor photoemission material are also revealed.

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“…Excitonic effects cause deviation from an independent-particle interpretation, but theory can determine their consequences and help to extract one-electron properties. Angle-resolved photoemission spectroscopy (ARPES) provides a more direct QP spectrum 4,5 . The data can be approximately related to the rigorously defined one-particle spectral function, ob-tained from the retarded Green's function G(k, ω) as 2,6 A(k, ω) = − 1 π mG R (k, ω),…”

Section: Introductionmentioning

confidence: 99%

Quasiparticles and phonon satellites in spectral functions of semiconductors and insulators: Cumulants applied to the full first-principles theory and the Fröhlich polaron

et al. 2018

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The electron-phonon interaction causes thermal and zero-point motion shifts of electron quasiparticle (QP) energies k (T ). Other consequences of interactions, visible in angle-resolved photoemission spectroscopy (ARPES) experiments, are broadening of QP peaks and appearance of sidebands, contained in the electron spectral function A(k, ω) = − mGR(k, ω)/π, where GR is the retarded Green's function. Electronic structure codes (e.g. using density-functional theory) are now available that compute the shifts and start to address broadening and sidebands. Here we consider MgO and LiF, and determine their nonadiabatic Migdal self energy. The spectral function obtained from the Dyson equation makes errors in the weight and energy of the QP peak and the position and weight of the phonon-induced sidebands. Only one phonon satellite appears, with an unphysically large energy difference (larger than the highest phonon energy) with respect to the QP peak. By contrast, the spectral function from a cumulant treatment of the same self energy is physically better, giving a quite accurate QP energy and several satellites approximately spaced by the LO phonon energy. In particular, the positions of the QP peak and first satellite agree closely with those found for the Fröhlich Hamiltonian by Mishchenko et al. (2000) using diagrammatic Monte Carlo. We provide a detailed comparison between the first-principles MgO and LiF results and those of the Fröhlich Hamiltonian. Such an analysis applies widely to materials with infra-red active phonons. We also compare the retarded and time-ordered cumulant treatments: they are equivalent for the Fröhlich Hamiltonian, and only slightly differ in first-principles electron-phonon results for wide-band gap materials.

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Photoemission Properties of Simple Metals

Cited by 104 publications

References 19 publications

Angle-dependent study of a direct optical transition in thespbands of Ag(111) by one- and two-photon photoemission

Angle-dependent study of a direct optical transition in thespbands of Ag(111) by one- and two-photon photoemission

Electron Band Alignment at Interfaces of Semiconductors with Insulating Oxides: An Internal Photoemission Study

Quasiparticles and phonon satellites in spectral functions of semiconductors and insulators: Cumulants applied to the full first-principles theory and the Fröhlich polaron

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