Federico Mazzola's area of research focuses on the electronic structure and properties of quantum materials ranging from semiconductors, semimetals, topological insulators to superconductors, with particular interest in the many-body interactions that underpin their physical properties and how these can be tuned using quantum confinement and modifying their crystalline symmetry. His work is motivated by the synthesis and study of novel systems, which could provide a suitable platform for integration with existing semiconductor-based technology.
2016 - Ph.D. in Physics at the Norwegian University of Science and technology (NTNU), Norway 2012 - Master's Degree in Physics at the Sapienza University of Rome, Italy 2010 - Bachelor Degree in Physics at the Sapienza University of Rome, Italy
Strong-coupling charge density wave in monolayer TiSe2
M.D. Watson, A. Rajan, T. Antonelli, K. Underwood, I. Marković, F. Mazzola, O.J. Clark, G.-R. Siemann, D. Biswas, A. Hunter, S. Jandura, J. Reichstetter, M. McLaren, P. Le Fèvre, G. Vinai and P.D.C. King
We study the 2×2 charge density wave (CDW) in epitaxially-grown monolayer TiSe2. Our temperature-dependent angle-resolved photoemission spectroscopy measurements indicate a strong-coupling instability, but reveal how not all states couple equally to the symmetry-breaking distortion, with an electron pocket persisting to low temperature as a non-bonding state. We further show how the CDW order can be suppressed by a modest doping of around 0.06(2) electrons per Ti. Our results provide an opportunity for quantitative comparison with a realistic tight-binding model, which emphasises a crucial role of structural aspects of the phase transition in understanding the hybridisation in the ground state. Together, our work provides a comprehensive understanding of the phenomenology of the CDW in TiSe2 in the 2D limit.
From our users
Phys. Rev. B, 101, 205125, (2020)
Direct observation of the energy gain underpinning ferromagnetic superexchange in the electronic structure of CrGeTe3
M.D. Watson, I. Marković, F. Mazzola, A. Rajan, E.A. Morales, D.M. Burn, T. Hesjedal, G. van der Laan, S. Mukherjee, T.K. Kim, C. Bigi, I. Vobornik, M.C. Hatnean, G. Balakrishnan and P.D.C. King
We investigate the temperature-dependent electronic structure of the van der Waals ferromagnet, CrGeTe3. Using angle-resolved photoemission spectroscopy, we identify atomic- and orbital-specific band shifts upon cooling through TC. From these, together with x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements, we identify the states created by a covalent bond between the Te 5p and the Cr eg orbitals as the primary driver of the ferromagnetic ordering in this system, while it is the Cr t2g states that carry the majority of the spin moment. The t2g states furthermore exhibit a marked bandwidth increase and a remarkable lifetime enhancement upon entering the ordered phase, pointing to a delicate interplay between localized and itinerant states in this family of layered ferromagnets.
Phys. Rev. B, 101, 035404, (2020)
Proximity-induced ferromagnetism and chemical reactivity in few-layer VSe2 heterostructures
G. Vinai, C. Bigi, A. Rajan, M. D. Watson, T.-L. Lee, F. Mazzola, S. Modesti, S. Barua, M. Ciomaga Hatnean, G. Balakrishnan, P.D.C. King, P. Torelli, G. Rossi, and G. Panaccione
Among transition-metal dichalcogenides, mono and few-layers thick VSe2 has gained much recent attention following claims of intrinsic room-temperature ferromagnetism in this system, which have nonetheless proved controversial. Here, we address the magnetic and chemical properties of Fe/VSe2 heterostructure by combining element sensitive x-ray absorption spectroscopy and photoemission spectroscopy. Our x-ray magnetic circular dichroism results confirm recent findings that both native mono/few-layer and bulk VSe2 do not show intrinsic ferromagnetic ordering. Nonetheless, we find that ferromagnetism can be induced, even at room temperature, after coupling with a Fe thin film layer, with antiparallel alignment of the moment on the V with respect to Fe. We further consider the chemical reactivity at the Fe/VSe2 interface and its relation with interfacial magnetic coupling.
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NFFA is a Progetto Internazionale financed by MIUR through CNR
(Istituto Officina dei Materiali, Trieste) and Elettra-Sincrotrone Trieste
and managed by the Commissione NFFA chaired by Giorgio Rossi
(Università di Milano and IOM-CNR).