Electronic states of moiré modulated Cu films.
We examined by low-energy electron diffraction and scanning tunneling microscopy the surface of thin Cu films on Pt(111). The Cu/Pt lattice mismatch induces a moiré modulation for films from 3 to about 10 ML thickness. We used angle-resolved photoemission spectroscopy to examine the effects of this structural modulation on the electronic states of the system. A series of hexagonal- and trigonal-like constant energy contours is found in the proximity of the Cu(111) zone boundaries. These electronic patterns are generated by Cu sp-quantum well state replicas, originating from multiple points of the reciprocal lattice associated with the moiré superstructure. Layer-dependent strain relaxation and hybridization with the substrate bands concur to determine the dispersion and energy position of the Cu Shockley surface state.
Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste, Italy. paolo.moras@trieste.ism.cnr.it
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Moras
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Sheverdyaeva
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Carbone
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Topwal
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Ferrari
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Bihlmayer
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Ouazi
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Rusponi
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Lehnert
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Brune