Controlled Interaction of Surface Quantum-Well Electronic States

• Published in: Nano letters Vol. 13; no. 12; pp. 6130 - 6135
• Main Authors: Seufert, Knud, Auwärter, Willi, Garcı́a de Abajo, F. J, Ecija, David, Vijayaraghavan, Saranyan, Joshi, Sushobhan, Barth, Johannes V
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11.12.2013
• Subjects: Arrays; Bonding; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Control surfaces; Coupling (molecular); Cross-disciplinary physics: materials science; rheology; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Electrons; Exact sciences and technology; Materials science; Mathematical analysis; Methods of nanofabrication; Microscopy, Scanning Tunneling; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wells; Self assembly; Silver - chemistry; Spectrum Analysis; Surface Properties; Wave functions; quantum dot; porphyrin; scanning tunneling spectroscopy (STS); Surface state; electron confinement; scanning tunneling microscopy (STM); Potential barrier; Electronic properties; Bound state; Quantum wells; Surface electron state; Hybridization; Surface states; Silver; Self-assembly; Manufacturing processes; Electron state; Wave functions; Scanning tunneling spectroscopy; Molecule manipulation; Arrays; Nanostructured materials; Porphyrins
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl403459m

We report on the construction of well-defined surface quantum well arrangements by combining self-assembly protocols and molecular manipulation procedures. After the controlled removal of individual porphyrin molecules from dense-packed arrays on Ag(111), the surface state electrons are confined at the bare silver patches. These act as quantum wells that show well-defined unoccupied bound surface states. Scanning tunneling spectroscopy and complementary boundary element method calculations are performed to characterize the interaction between the bound states of adjacent quantum wells and reveal a hybridization of wave functions resulting in bonding and antibonding states. The interwell coupling can be tuned by the deliberate choice of the molecules acting as potential barriers. The fabrication method is shown to be ideally suited to engineer specific configurations as one-dimensional chains or two-dimensional artificial molecules.