STSON NANOSTRUCTURES · Investigation of the electronic properties of nanostructures at the atomic scale by means of low temperature scanning tunneling microscopy/spectroscopy in ultrahigh vacuum conditions
FP7 — People (Marie Curie Actions)
- Duration
- 2009-11-01 → 2012-10-31
- EU contribution
- €45,000
- Participants
- 1
- Scheme
- MC-ERG
Lines connect the coordinator with its partners.
Results in brief
Investigation of the electronic properties of nanostructures at the atomic scale by means of low temperature scanning tunneling microscopy/spectroscopy in ultrahigh vacuum conditions
This project investigates, at the atomic level, the structural and electronic properties of nanostructures by means of a low temperature scanning tunnelling microscopy/spectroscopy in ultrahigh-vacuum environments (UHV-LTSTM). This allowed the study of these properties in a local way with atomic precision and ultimate energy resolution and also to modify the systems in a controlled way by direct manipulation using the STM tip. The main results achieved are described in the following: Impact of point defects in graphene Systems How does the presence of single atomic defects modify the properties of materials? Such a general and fundamental question was addressed in this project for atomic vacancies in graphene systems, where the presence of such defects is expected to have a dramatic impact in its properties due to graphene's pure bidimensionality. Introducing vacancies in graphene-like systems by irradiation has been shown to be an efficient method to vary its mechanical behavior, tune its electronic properties and even to induce magnetism in otherwise non-magnetic samples. While the role played by these vacancies as single entities has been extensively addressed by theory, experimental data available refer to statistical properties of the whole heterogeneous collection of vacancies generated in the irradiation process. In this project we have overcome this limitation: we first created perfectly characterized single vacancies on graphene layers by Ar+ ion irradiation and then, using low temperature scanning tunneling microscopy (LT-STM), we individually investigated the impact of each of such vacancies in the electronic, structural and magnetic properties of several graphene systems. Our work demonstrated that vacancies lead to a dramatic reduction of the electronic mobility and confirmed the creation of magnetic moments associated to the vacancies in this pure carbon material, indicating a suitable route to the creation of non-metallic, cheaper, lighter, and bio-compatible magnets. Thanks to this absolutely pioneering works, planned and developed since the beginning of the present ERG project, our group has become a world-leading reference in the field. Our first work, which was published in 2010 in Physical Review Letters, has received already more than hundred citations, being the 10th (out of 3512) most cited paper in PRL this year. Research performed in this field since then has continued with this successful tendency as reflected in the new publications in Physical Review Letters and Physical Review B and on paper in revision in Science. The works have been highlighted in Physical Review Focus, PhysOrg.com or Physics.
Data: CORDIS, © European Union
Project objective
The main goal of the research project that I propose for the next three years is the study of the electronic properties of nanostructures at the atomic scale. The investigation will be performed by means of low temperature scanning tunnelling microscopy/spectroscopy in ultrahigh-vacuum environments (UHV-LTSTM), a unique technique which allows the study of these electronic properties in a local way with atomic resolution. Thanks to this technique it will be possible to get the local electronic information of the nanostructures with ultimate energy resolution (<1meV) and also to modify the systems in a controlled way by direct manipulation using the STM tip. This will open the possibility to selectively modify the local environment of the nanostructures to study and also to create new nanostructures using as elemental building-blocks atoms and/or individual molecules. The investigation will be structured in three main research lines: On one side the electronic properties of nanostructures electronically decoupled from the substrate by means of ultrathin insulating films will be studied Two main kind of nanostructures will be examined; bidimensional metallic films and molecules both in single and self-assembled arrangements. In a second line these same nanostructures, now adsorbed on epitaxial graphene, will be investigated. Special emphasis will be put in the influence of the Dirac quasiparticles of graphene in the electronic properties of the nanostructures and also in understanding and/or controlling how the adsorption of these nanostructures locally or even globally modify the electronic properties of graphene itself. The third research line will be focused on the study of phase transitions in the metal semiconductor systems Pb/Si(111), Pb/Ge(111) and Sn/Ge(111) at 4K. One of the fundamental questions to understand the temperature evolution of these 2D systems is precisely to know which is the true ground state at the lowest temperature.
Original text from CORDIS.
Participants
- UNIVERSIDAD AUTONOMA DE MADRID · MadridCoordinatorSpain
Links
Data: CORDIS, © European Union