Anisotropic Metal-Insulator Transition in Epitaxial Thin Films

Altfeder, Igor; Liang, Xiaomeng; Yamada, Toshio; Chen, D. M.; Narayanamurti, V.

doi:10.1103/physrevlett.92.226404

Cited by 27 publications

(29 citation statements)

References 25 publications

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“…94) More recently, the lateral bound states were observed in Pb and In thin films, a lateral electron confinement due to quantum enhancement of Coulomb interaction was proposed to interpret the results. 156) However, the ARPES measurement suggests a strongly enhanced lateral electron localization (the lateral effective masses in Pb/Si(111) QWS are up to an order of magnitude larger than those from the bulk states or predicted by slab calculations), which was only observed in Pb/Si(111) but not in In/Si(111) system. 157) According to the phase accumulation model, 2,3) the substrate and interface are crucial in the formation of QWS and affect film properties in a significant way as well.…”

Section: Discussionmentioning

confidence: 97%

Quantum Size Effects Induced Novel Properties in Two-Dimensional Electronic Systems: Pb Thin Films on Si(111)

Jia

Zhang

et al. 2007

J. Phys. Soc. Jpn.

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Atomically flat metal ultrathin films grown on semiconductor substrates form a quasi-two-dimensional (2D) electronic system, which offers a great opportunity to explore novel properties induced by quantum size effects (QSE). In such a system, the motion of electrons in the film plane is essentially free, however, in the film normal direction it is confined, which leads to the quantized electronic states, i.e., quantum well states (QWS). The formation of QWS induces the redistribution of electrons and changes the electronic structure of the metal films and thus modifies their properties. By controlling the film thickness-the width of the confinement potential well, the QWS, together with the physical and chemical properties of the films can be engineered. In this article, we will summarize our recent studies on this problem in the Pb/Si(111) system, and discuss the perspectives in this area.

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Section: Discussionmentioning

confidence: 97%

Quantum Size Effects Induced Novel Properties in Two-Dimensional Electronic Systems: Pb Thin Films on Si(111)

Jia

Zhang

et al. 2007

J. Phys. Soc. Jpn.

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“…The growth of In films on Si(111) has been examined by a number of authors [9,10,11,12,13,14,15]. For example, films grown on a Si(111)-(6×6)-Au surface showed subtle features in the electrical mean free path at 3, 6, and 9 ML thicknesses, which was interpreted in terms of roughness oscillations in the films [12].…”

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confidence: 99%

X-ray diffraction studies of trilayer oscillations in the preferred thickness of In films on Si(111)

2013

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“…This localization idea was also proposed earlier in a scanning tunneling microscopy study of the same system. 35 Conceptually, localization could occur in thin films for two possible reasons. One is that the confined geometry could force overlap of the wave functions, resulting in enhanced correlation effects and a modified dispersion relation.…”

Section: Resultsmentioning

confidence: 99%

Quantized electronic structure and growth of Pb films on highly oriented pyrolytic graphite

et al. 2008

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We have measured the electronic structure of thin Pb films grown on highly oriented pyrolytic graphite ͑HOPG͒ by angle-resolved photoemission spectroscopy. Quantum well states ͑QWSs͒ corresponding to confined Pb valence electrons are observed. Their energy positions are fixed, but their intensities evolve for increasing Pb coverages. The results indicate that the films are rough, consisting of multiple thicknesses. Nevertheless, the thickness distribution is sufficiently narrow to allow a unique assignment for each QWS peak in terms of a quantum number and the exact film thickness in atomic layers. For increasing Pb coverages of up to 10 monolayers ͑ML͒, the even film thicknesses of 2, 4, 6, 8, and 10 ML are much more prevalent than the odd film thicknesses of 1, 3, 5, 7, and 9 ML, thus suggesting significant differences in surface energy between the even and odd thicknesses. These results are consistent with an available first-principles calculation of the surface energies of freestanding films; an implication is that the interaction between the Pb film and the HOPG substrate is weak. The in-plane dispersion relations of the QWSs are measured. The effective masses at the surface zone center agree well with the results calculated from the bulk Pb band structure, in sharp contrast to the strongly enhanced or anomalous effective masses in Pb films grown on Si͑111͒ as reported previously. This finding indicates that the anomalous effective masses in Pb/Si͑111͒ are not caused by increased electron correlation effects in a confined geometry, but are rather attributable to a strong interfacial interaction between the QWSs and the substrate electronic structure.

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Anisotropic Metal-Insulator Transition in Epitaxial Thin Films

Cited by 27 publications

References 25 publications

Quantum Size Effects Induced Novel Properties in Two-Dimensional Electronic Systems: Pb Thin Films on Si(111)

Quantum Size Effects Induced Novel Properties in Two-Dimensional Electronic Systems: Pb Thin Films on Si(111)

X-ray diffraction studies of trilayer oscillations in the preferred thickness of In films on Si(111)

Quantized electronic structure and growth of Pb films on highly oriented pyrolytic graphite

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