Final Report Summary - 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)
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.
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.