THEMES PROPOSED FOR THE XXXIII CICLE OF PhD in PHYSICS AND NANOSCIENCES (3 years starting from Nov. 2017)

EXPERIMENTAL THESIS THEMES
  • Title: Assessment of new measurement paradigms in electron microscopy
  • Tutor: Prof. Stefano Frabboni, Dr. V. Grillo (CNR-S3)
    Abstract: This research proposal leverages the newly-acquired capacity to structure electron beams and to measure free-electron orbital angular momentum in the transmission electron microscope [1]. It involves tuning the electron probe according to the property of interest in the sample and performing post-interaction analysis over the most appropriate basis of quantum states. Applications: magnetism at the nanoscale, protein complexes recognition, plasmonic nanostructures.
    The candidate (preferably with experimental and optionally with computational skills) will be part of the international research team of the Q-Sort project (FET open-01-2016-2017.1 Approved -june 2017.)
    [1] V. Grillo et al. https://www.nature.com/articles/ncomms15536
    External fellowship available: yes.

  • Title: Charge excitations in metal/oxide nanostructures
  • Tutor: Dr. Paola Luches, Prof. Sergio Valeri
    Abstract: The proposed work aims at the study of charge excitations in plasmonic-metal nanoparticles combined with reducible oxides. The goal is to obtain materials with increased light harvesting efficiency and with an optimized concentration of long-lived excited states, which can provide charge to the environment. This will be achieved by addressing the time-dependent decay of excited states in systems with different architectures. The work will be carried out in the framework of a PRIN project, in collaboration with the University of Bologna and with partners at large scale facilities hosting ultra-fast techniques, like ESRF, FERMI@ELETTRA, and CNR-ISM.
    External fellowship available: not available at the moment.

  • Title: Growth and functional properties of physically synthesized metal/ metal oxides core-shell nanoparticles
  • Tutor: Prof. Sergio D’Addato
    Abstract: The interest in metal nanostructured films has grown in the last years because of their fascinating physical properties and their potentiality in various applications, like magnetic recording industry, catalysis and plasmonics. We propose a PhD thesis devoted to the investigation of metal and core-shell oxide-metal nanoparticles physically synthesized with a gas aggregation source which is able to produce and mass-select clusters. The study will be focused on the structure, chemical and magnetic properties of the individual particles and of the nanoparticle assembled films. Some of the techniques to be used in campus will be XPS, SEM, TEM and visible-UV Reflectivity. Part of the experimental activity will be also carried out in external facilities like synchrotrons (XAFS, PEEM and XMCD experiments), in collaboration with other groups.
    External fellowship available: no.

  • Title: Mechanical properties of living cells
  • Tutor: Prof. Andrea Alessandrini
    Abstract: The thesis project involves the exploitation of different experimental techniques (atomic force microscopy, micropipette aspiration, fluorescence microscopy) to investigate the mechanical properties of living cells in relation to their pathological conditions and to the different scaffolds and substrates on which they are growing. The effect of the substrate physical and chemical properties on the cell fate will be investigated. The effects of chemical and physical treatments targeting mechanical components of the cell (cytoskeleton) will be studied. The activity is also framed within a large project with the involvement of groups working on the development of new advanced scaffolds for bone transplantation. The activity will also include the development of new set-ups to increase the throughput such as optical stretching devices coupled to microfluidic set-ups. All the project will be performed within a highly interdisciplinary environment.
    Collaborations: Dipartimento di Scienze della Vita, UniversitÓ di Modena e Reggio Emilia CNR-ISTEC- Faenza
    Supplementary information: The Project is framed within the Regional Project POR-FESR 2014-2020 NIPROGEN: La natura ispira processi innovativi per lo sviluppo di impianti per la medicina rigenerativa a elevato grado di vascolarizzazione e performance meccaniche.

  • Title: On-surface synthesis and characterization of graphene-based nanostructures
  • Tutor: Prof. Valentina De Renzi
    Abstract: On-surface synthesis represents a promising approach to achieve atomic-precise graphene-based nanostructures1, as in particular graphene nanoribbons (GNR)2. These systems can be considered as building blocks for more complex self-assembled structures with possible applications in optoelectronics and spintronics3,4. In the proposed work, these systems will be grown and investigated by means of XPS, ARUPS, HREELS, LEED, STM and by synchrotron radiation based techniques.
    [1] L. Lafferentz et al. Nat. Chem 2012 4, 215 [2] J. Cai et al., Nat. 2010 466, 470 [3] S. Kattel, RSC Adv., 2013, 3, 21110–21117 [4] H. Sevinšli, Phys. Rev. B 77, 195434 (2008)
    Collaborations: A. Narita and K. Muellen, Istitut for polymer science MPG Mainz; A. Ruini, D. Prezzi, A. Ferretti FIM Department & S3-CNR-Nano
    External fellowship available: no.

  • Title: Quantum Technology: Coupling spins with microwave photons
  • Tutor: Prof M. Affronte (marco.affronte@unimore.it) and dr. A. Ghirri
    Abstract: One challenge of Quantum Technologies is the coherent manipulation and the read-out of quantum objects by photons. This proposal aims at the development of hybrid devices for pulsed-microwave magnetic resonance experiments. The first objective of the thesis is the realization of the experimental set-up, which combines planar microwave resonators and nanofabricated magneto-transport contacts, for the study of low-dimensional like spin systems molecular spins or nanowires. Transmission spectroscopy experiments will be initially carried out in continuous wave mode and subsequently extended to pulse sequences for the coherent manipulation of the spins. The experiments will be partially carried out at international high magnetic field facilities and in collaboration with leading international laboratories in Florida (US), Osaka (Jp), Grenoble (F) and Karlsruhe (D).
    Reference: APL 106, 184101 (2015), Dalton Trans. 45, 16596–16603 (2016)
    External fellowship available: possible.

  • Title: Molecular approaches to nanoscale magnets
  • Tutor: Prof. Andrea Cornia (acornia@unimore.it)
    Abstract: The proposed research activity, to be carried out at the Dept. of Chemical and Geological Sciences, targets the design of artificial nanosized molecules behaving as miniaturized magnets for applications in memory devices and spintronics. As a key aspect, our strategy relies on metal-metal bonds to boost molecular magnetism (R. H. Sa┤nchez, T. A. Betley, J. Am. Chem. Soc. 2015, 137, 13949). Collaboration is planned with national and international laboratories involved in COST Action MOLSPIN (http://www.icmol.es/molspin). Techniques: organic/organometallic synthesis, handling of air- and water-sensitive compounds, mass spectrometries, XRD, magnetic measurements and EPR.
    External fellowship: no.

  • Title: Molecular Quantum Spintronics
  • Tutor: Dr. A. Soncini (asoncini@unimelb.edu.au), Prof. M. Affronte (marco.affronte@unimore.it)
    Abstract: we propose to study quantum effects in single-molecule spintronic devices as depicted at: http://www.moquas.eu/. The thesis work can be either theoretical, under the supervision of Dr. Soncini at Univ. of Melbourne (AUS), or experimental comprising fabrication and low temperature characterization of molecular devices in collaboration with CNR Nano (Dr. A. Candini), Inst. L. NÚel (Grenoble, F), Karlsruhe (D).
    External fellowship available: no at the moment.

  • Title: Charge transport in 2D nanosheet-network materials. Role of physico-chemical properties of single sheet and network geometry
  • Tutor: Dr. Vincenzo Palermo
    Abstract: The using of 2D materials in printable electronics requires a set of emerging technologies that includes new materials, process equipment, and devices.[Kelly et al., Science 356 (2017), 69] The thesis focuses on studying the correlation between the physico-chemical properties of the single sheet, the network geometry and the collective electrical/magnetic properties of the printed material. Collaboration: CNR (2D sheets production & deposition, AFM, XPS), Affronte R(T) measurements, Corradini (HREELS) T
    External fellowship: external grants Flagship Core1/2.

  • Title: Design suitable fabrication strategies for electrical and optical properties tunability and thermal stability of Ti-oxide thin films (EXP)
  • Tutor: Sergio Valeri
    co-Tutor: Alessandro di Bona
    Abstract: The proposed activity aims at a comprehensive experimental assessment and comparison of the phase stability, defect structure, chemical reactivity, transport and electronic properties of a scientifically and technologically relevant material, namely Ti-oxide thin films, prepared by different deposition methods (MBE, magnetron sputtering and thermal oxidation of pure metal), oriented to design suitable fabrication strategies for electrical and optical properties tunability, thermal stability and cyclability.
    External fellowship: no.

  • Title: Nano mechanics at surfaces and interfaces (EXP)
  • Tutor: Sergio Valeri
    co-Tutor: Diego Marchetto, Guido Paolicelli
    Abstract: The proposed activity is oriented to explore how and to what extent friction and wear are influenced by nano- microstructures on and beneath the surface. These structures can be both natural (crystalline grains, dislocations, roughness…) and artificial (surface nanostructures, nano- micro multilayers, …). For this study several experimental techniques must be used, including scanning probe friction force microscopy and micro tribometers for tribological analysis (respectively at the nano and micro scale), and electron microscopies and spectroscopies for structural and chemical investigation.
    M.Tripathi, F.Awaja, G.Paolicelli,R.Bartali, E.Iacob, S.Valeri, S.Ryu, S.Signetti, Stefano, G.Speranza, N.M.Pugno, “Tribological characteristics of few-layer graphene over Ni grain and interface boundaries” , Nanoscale 8 (12), 6646-6658 (2016). IF: 7.4
    External fellowship: no.

THEORETICAL THESIS THEMES
  • Title: Materials to reduce friction by atomistic simulations
    Tutor: Dr. M. Clelia Righi
    Abstract: The technologies nowadays available to reduce friction are based on materials, such as solid/liquid lubricants and hard coatings. Here the project is to apply ab initio and classical molecular dynamics to study the physical/chemical processes that rule the functionality of lubricant materials, particularly those used in automotive applications. A fundamental understanding of the effects of mechanical forces on reaction kinetics is a further scope of the project. The activity will involve collaboration with the industries Total S.A. and Toyota R&D Labs.
    External fellowship: possible.

  • Title: Dimensional crossover in a system of a few Fermi atoms
    Tutor: Dr. Massimo Rontani
    Abstract: Ultracold Fermi atoms are at the core of quantum technologies because they allow for the exquisite experimental control of key degrees of freedom. Besides, they are a heaven for theorists since they realize textbook-like models of interacting fermions with tunable interactions. This project aims to obtain exact theoretical results for few interacting atoms as the dimensionality of the optical trap is changed from a quasi 1D to a fully 3D system, with emphasis on the link between superfluidity and dimensional crossover. The theoretical tools employed involve both semi-analytical approaches as well as the full configuration interaction numerical method (also known as exact diagonalization), the latter being implemented in the DonRodrigo code developed in house. A strong interaction with the theory group at Lund University (Sweden), under the additional supervision of Prof. S. M. Reimann, is foreseen.
    External fellowship: no external grants.

  • Title: Plasmonics in metal/metal oxides core-shell nanoparticles
    Tutor: Prof. Rita Magri
    Abstract: Plasmonics at the nanoscale is a very interesting new area of exploration with a number of important applications in many areas, from biosensing to clean energy production. The thesis will tackle with the design of nanoparticle structures in order to optimize their plasmonic response. The idea is to engineer the surface plasmon resonances by varying the geometry and the composition of metal nanoparticles enclosed by a reducible oxide cavity shell. Since the plasmon resonances depend on the details of the nanostructure, this opens up numerous ways to control and manipulate light at nanoscale dimensions. Both classical modeling and ab-initio methods will be employed. The work will be performed in strict contact with the experimental group at the University of Modena and Reggio Emilia and CNR-Nano growing and characterizing the nanoparticles.
    External fellowship: no.

  • Title: Design of quantum dot structures in nanowires
    Tutor: Prof. Rita Magri
    Abstract: This thesis work addresses the atomistic modeling and the electronic structure of quantum dots structures (zero-dimensional systems) embedded in nanowires (one-dimensional systems), which are systems with a huge potential for a number of device applications. These systems have been realized recently and can be obtained using a number of different strategies. However, given the huge number of atoms required for their atomistic description hybrid “horizontal” multiscale method (ab-initio and semiempirical approaches) needs to be developed and applied. This project will be developed in collaboration with research groups in Brazil and UK.
    External fellowship: no.

  • Title: Time-dependent dynamics of quantum complexes
    Tutor: Prof. Guido Goldoni (guido.goldoni@unimore.it), Dr. Andrea Bertoni (andrea.bertoni@nano.cnr.it)
    Abstract: When quantum composite particles —such as small molecules, nuclei, or electron-hole pairs in semiconductors— are scattered by an external potential, energy may be transferred between center of mass (CoM) and internal degrees of freedom. Accurate dynamical modeling of the internal dynamics is critical to predict scattering coefficients and reaction cross sections, and allows us to rationalize time-resolved spectroscopies. Exact solution of both internal and CoM degrees of freedom by Schr÷edinger equation is in principle always possible, but it requires the use of massively parallel computers and it is limited to few degrees of freedom (e.g. in one dimensional systems). We have recently developed a method for the time-dependent evolution of a quantum complex scattering against an arbitrary, non-perturbative external potential which allows to propagate the CoM only (hence with a huge computational advantage) in a properly designed local self-energy potential which embeds the effect of internal transitions. In this thesis we indent to simulate excitons (electron-hole pairs in semiconducturs) both in single-exciton devices and in exciton gases in the Bose-Einstein condensate. The candidate will acquire a working knowledge in advanced modelling of nano-materials and simulative methods in quantum physics, as well as in the development of high performance software for parallel architectures. In this very innovative field of research the specific aspect investigated and theoretical/computational approaches can be tailored the candidate’s background, skills and interests.
    Main references:
    [1] Space- and time-dependent quantum dynamics of spatially indirect excitons in semiconductor heterostructures, J. Chem. Phys. 142, 034701 (2015)
    [2] Exact two-body quantum dynamics of an electron-hole pair in semiconductor coupled quantum wells: a time-dependent approach Phys. Rev. B 93, 195310 (2016)
    [3] Time-dependent scattering of a composite particle: A local self-energy approach for internal excitations Phys. Rev. B 94, 125418 (2016)

  • Title: Core-shell nanowires: nano-materials for the next generation nano-opto-electronics
    Tutor: Prof. Guido Goldoni (guido.goldoni@unimore.it), Andrea Bertoni (andrea.bertoni@nano.cnr.it)
    Abstract: Abstract: Core-shell nanowires are innovative nano-materials, similar to long nano-needles. Material modulation both along and radially to the axis allow to tailor their electronic properties to a high degree. This opens a wide range of application in nano-opto-electronics. At the same time, the electronic system is confined to new topologies, which opens to new quantum phenomena. This thesis will focus on the fundamentals of the electronic states of these nano-materials, with an emphasis on their thermo-electric properties, specifically addressing ongoing experimental activities. The activity is of a theoretical/computational character. The candidate will acquire a working knowledge in advanced modelling of nano-materials and simulative methods in quantum nano-devices, as well as in the development of high performance software for parallel architectures.
    Main references:
    [1] High mobility one- and two- dimensional electron systems in nanowire-based quantum heterostructures, Nano Lett. 13, 6189 (2013)
    [2] Unintentional p-type doping of a GaAs/AlAs core-multi-shell nanowire revealed by resonant phonon coupling, Nano Lett. 14, 2807-2814 (2014)
    [3] Tailoring the core electron density in modulation-doped Core-Multi-Shell Nanowires, Nanotechnology 27, 195201 (2016)

  • Title: Quantum correlations in few-particles nanostructures
    Tutor: Dr. Paolo Bordone (bordone@unimore.it), Dr. Andrea Bertoni (andre.bertoni@cnr.it)
    Abstract: This thesis addresses the exact quantum dynamics of few-particles systems in semiconductor nanostructures. We developed a numerical code for the time-dependent solution of the Schroedinger equation in 2D systems, suitable to investigate entanglement and interference phenomena in 2D nanostructures. In particular we intend to explore the potentialities of edge states in the QH regime for possible implementations of quantum computing devices. 1) A. Beggi, P. Bordone, F. Buscemi, A. Bertoni, J. Phys.: Condens. Matter 27, 475301 (2015).
    External fellowship: no.

  • Title: Quantum walks in bidimensional systems in the presence of external fields
    Tutor: Dr. Paolo Bordone (bordone@unimore.it)
    Abstract: This thesis focuses on the analysis of quantum walks of a particle on a bidimensional graph in the presence of an external field (magnetic and/or electrical). Preliminary studies have shown peculiar effects as for example Bloch’s oscillations and Schroedinger cat’s states formation when a transverse magnetic field is introduced. The next step is the analysis of the effects of a noisy lattice on the walker dynamics and the introduction of nontrivial connections among the nodes of the graph besides the possibility of long range hopping.
    [1] C. Benedetti, F. Buscemi, P. Bordone, M.G.A. Paris, “Non.Markovian continuous-time quantum walks on lattice with dynamical noise”, Phs. Rev. A 93, 042313 (2016). [2] I. Siloi, C. Benedetti, E. Piccinini, J. Piilo, S. Maniscalco, M.G.A. Paris, P. Bordone, “Noisy quantum walks of two indistinguishable interacting particles”, Phys. Rev. A 95, 022106 (2017).
    External fellowship: no.

  • Title: First-principle simulation of high harmonic generation orbital tomography
    Tutor: Massimo Rontani (CnrNano)
    co-Tutor: Daniele Varsano (CnrNano)
    External Collaborations: Stefano Corni (Universita di Padova)
    Abstract: High Harmonic Generation (HHG), a strongly non-linear optical process, has been experimentally investigated as a tool to disclose the undisputed signature of the quantum nature of electrons in molecules, i.e., the molecular orbitals. Many-body effects, beyond the independent particle picture, are also contained in the experimental results. However, the interpretation of the HHG experiments and the reconstruction of the orbitals is currently hampered by several assumptions. First principle simulations are needed to overcome them. The PhD project consists in developing and applying the necessary first-principle approaches to model the HHG experiments and provide improved techniques to extract the orbital shapes. It involves national and international collaboration with experimental and theoretical groups.
    External fellowship: no.

  • Title: Self-interaction in many-body perturbation theory: a diagrammatic approach
    Tutor: Elisa Molinari (UniMoRe)
    co-Tutor: Andrea Ferretti (CnrNano)
    Abstract: The concepts of self-interaction error and total energy piece-wise linearity have been linked together and recently extensively used as a way to characterize, for instance, the quality of exchange-correlation approximations in density functional theory.In this thesis we propose to follow the same route in order to characterize electronic structure methods such as those arising from many-body perturbation theory (MBPT) (e.g. the GW, second-Bohr approximations, SOSEX, etc). The thesis work is expected to be both theoretical and computational, with the latter aspect very central in the research activity of the candidate.
    External fellowship: no.

  • Title: First-principle simulation of photoemission and absorption spectroscopy in experimental condition.
    Tutor: Prof. Elisa Molinari (UniMoRe)
    co-Tutor: Daniele Varsano (CnrNano)
    Abstract: Photoemission and absorption spectroscopy are ubiquitous experimental tools to investigate the electronic and optical properties of matter. Accurate thoretical calculations based on first principle are needed to provide interpretation of these experiments and Many Body Perturbation Theory (MBPT) is nowadays a very powerful theoretical framework that allows to takes into account electronic correlation and electron-hole interaction. However, due to the computational diffuculties to treat a very large number of atoms, ususally calculations are performed on isolated systems, ie discarding environment effects (solvent, substrate) which can have a large impact on the final measure.
    The PhD project consists in developing and applying a theoretical framework permitting to take into account in an effective way the influence of environmental effects in photoemission and absorption spectra in order to make possible direct comparison with experiments.
    Collaboration with experimental groups are envisaged.
    External fellowship: no additional scholarship available.

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