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Vertical bonding distances and interfacial band structure of PTCDA on a Sn-Ag surface alloy

DOI: 10.1103/PhysRevB.102.075447 DOI Help

Authors: Johannes Knippertz (University of Kaiserslautern) , Leah L. Kelly (University of Kaiserslautern) , Markus Franke (Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich; Jülich-Aachen Research Alliance (JARA)–Fundamentals of Future Information Technology) , Christian Kumpf (Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich; Jülich-Aachen Research Alliance (JARA)–Fundamentals of Future Information Technology) , Mirko Cinchetti (Technische Universität Dortmund) , Martin Aeschlimann (University of Kaiserslautern) , Benjamin Stadtmueller (University of Kaiserslautern; Graduate School of Excellence Materials Science in Mainz)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 102

State: Published (Approved)
Published: August 2020
Diamond Proposal Number(s): 13773

Abstract: Molecular materials enable a vast variety of functionalities for novel electronic and spintronic devices. The unique possibility to alter organic molecules or metallic substrates offers the opportunity to optimize interfacial properties for almost any desired field of application. For this reason, we extend the successful approach to control metal-organic interfaces by surface alloying. We present a comprehensive characterization of the structural and electronic properties of the interface formed between the prototypical molecule PTCDA and a Sn-Ag surface alloy grown on an Ag(111) single crystal surface. We monitor the changes of adsorption height of the surface alloy atoms and electronic valence band structure upon adsorption of one layer of PTCDA using the normal incidence x-ray standing wave technique in combination with momentum-resolved photoelectron spectroscopy. We find that the vertical buckling and the surface band structure of the Sn Ag 2 surface alloy is not altered by the adsorption of one layer of PTCDA, in contrast to our recent study of PTCDA on a Pb Ag 2 surface alloy [B. Stadtmüller et al., Phys. Rev. Lett. 117, 096805 (2016)]. In addition, the vertical adsorption geometry of PTCDA and the interfacial energy level alignment indicate the absence of any chemical interaction between the molecule and the surface alloy. We attribute the different interactions at these PTCDA/surface alloy interfaces to the presence or absence of local σ -bonds between the PTCDA oxygen atoms and the surface atoms. Combining our findings with results from literature, we are able to propose an empiric rule for engineering the surface band structure of alloys by adsorption of organic molecules.

Journal Keywords: Adsorption; Electronic structure; Surface & interfacial phenomena; Surface states Physical Systems; Electron microscopy; Photoelectron techniques; Photoemission spectroscopy; X-ray standing waves

Diamond Keywords: Alloys

Subject Areas: Materials, Physics

Instruments: I09-Surface and Interface Structural Analysis

Added On: 09/09/2020 15:58

Discipline Tags:

Surfaces Hard condensed matter - electronic properties Physics Hard condensed matter - structures Electronics Materials Science interfaces and thin films Metallurgy

Technical Tags:

Diffraction X-ray Standing Wave (XSW)