Quantum well states, resonances and stability of metallic overlayers

Ogando, E.; Zabala, Nerea; Chulkov, Eugene V.; Puska, Martti J.

doi:10.1088/0953-8984/20/31/315002

Cited by 4 publications

(3 citation statements)

References 41 publications

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“…A number of topics have been addressed, such as the electron confinement in the overlayers due to the projected band gap in -L direction, the magic height distributions at different coverages, and the lifetimes of QWSs and quantum well resonances (QWRs). 37,[48][49][50] The present study extends our recent work 50 on the energies and lifetimes of the QWSs and QWRs in Pb/Cu(111). We address theoretically recent STM and STS experiments on confined states in large Pb(111) islands deposited on Cu(111) and Ag(111) surfaces.…”

Section: Introductionsupporting

confidence: 81%

Theoretical study of constant current scanning tunneling spectroscopy in Pb overlayers

et al. 2011

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We present a theoretical study of the constant current scanning tunneling spectroscopy of quantum well states localized in Pb(111) overlayers on Cu(111) surfaces. The distance-voltage characteristic of the tunneling junction is obtained with a mixed approach. The wave packet propagation technique is applied to describe electron tunneling from the tip into the sample, and the density functional calculations provide the necessary inputs for the one-dimensional model potential representation of the system. The excited-state population decay mechanisms via inelastic electron-electron and electron-phonon interactions are taken into account with a bias-dependent absorbing potential introduced in the metal. Our results are in good agreement with recent experimental studies [Phys. Rev. Lett. 102, 196102 (2009), Phys. Rev. B 81, 205438 (2010)] over the energy range where the free-electron description of the Pb overlayer used here applies. We find that at high bias the quantum well states experience a Stark energy shift and partially acquire a character of field emission resonances. The present model study also sheds light at the experimentally observed departure of the energies of the quantum well states from the particle-in-a-box prediction for the bias above 4 eV. The measured trend can be consistently explained as due to the departure of the realistic Pb band structure in the -L direction from free-electron parabola when the electron momentum approaches the point.

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Section: Introductionsupporting

confidence: 81%

Theoretical study of constant current scanning tunneling spectroscopy in Pb overlayers

et al. 2011

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“…Essentially the same conclusions follow from the more refined analytical treatment of the properties of the QWRs as reported in Ref. 59. Intuitively, the resonances become narrower, but their density increases so that in the limit of large d the continuum of Pb states is retrieved ͑see also Fig.…”

Section: Decay Of Quantum Well Resonancessupporting

confidence: 74%

Lifetimes of quantum well states and resonances in Pb overlayers on Cu(111)

et al. 2009

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We present results of calculations of the lifetimes of excited electrons ͑holes͒ in quantum well states and quantum well resonances in Pb overlayers supported on Cu͑111͒. Many-body decay via inelastic energy relaxation and one-electron decay via energy-conserving one-electron transfer into the substrate are considered. One-electron energies and wave functions have been computed for different coverages of the Pb overlayer ͑from 1 to 18 monolayers͒ by using a one-dimensional pseudopotential for the entire overlayer-substrate system in the framework of density functional theory within the local density approximation. The elastic ͑energy-conserving resonant electron transfer͒ contribution to the total lifetime broadening of quantum well resonances has been calculated within the wave packet propagation method. The inelastic electron-electron ͑many-body͒ contribution to the lifetime broadening of both occupied and unoccupied quantum well states has been evaluated using GW approximation. The decay mechanisms of both quantum well states and quantum well resonances in thick overlayers are discussed.

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“…7 If the electronic energy is roughly in the bulk gap, the electron cannot propagate inside the bulk crystal and will be reflected backward forming quantum well resonance (QWr). 8 If the energy of an electron is smaller than the work function, the electron is therefore confined by the crystal surface potential. Therefore, the confined electronic states around the film surface will decay in a parabolic scaling like QWS.…”

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confidence: 99%

Surface confined quantum well state in MoS2(0001) thin film

Song

Meng

et al. 2015

Applied Physics Letters

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Surface confined quantum well state (scQWS) is a QWS confined around the surface of a thin film whose electronic energy is smaller than the work function of the film. The scQWS is rather rare in most thin films. Here, we show the existence of scQWS in thin films of transition metal dichalcogenides, MoS 2 . Signatures of scQWS are identified as the overall downward band dispersion in the bulk gap of 2 H-MoS 2 thin film at larger binding energy range. These scQWSs are also characterized with a Shockley-type surface state having an inverse parabolic decay into the film and a symmetric (asymmetric) distribution of projected charge density at the two surfaces of odd-layer (even-layer) films. Our findings of scQWS in MoS 2 shed some light on understanding the electronic properties of 2D materials with implications in future 2D electronic devices. V C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4934610] APPLIED PHYSICS LETTERS 107, 161602 (2015) This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 155.98.2.187On: Thu, 05 Nov 2015 21:55:41 161602-2Sun et al.

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Quantum well states, resonances and stability of metallic overlayers

Cited by 4 publications

References 41 publications

Theoretical study of constant current scanning tunneling spectroscopy in Pb overlayers

Theoretical study of constant current scanning tunneling spectroscopy in Pb overlayers

Lifetimes of quantum well states and resonances in Pb overlayers on Cu(111)

Surface confined quantum well state in MoS2(0001) thin film

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