Publications by Gianmarco Gatti

Electron Glass Phase with Resilient Zhang-Rice Singlets in LiCu3O3

László Forró, Rosario Scopelliti, Arnaud Magrez, Krunoslav Prsa, Henrik Moodysson Rønnow, Simon Karl Moser, Jens Christian Johannsen, Paul Gregory Freeman, Edoardo Martino, Gianmarco Gatti

LiCu3O3 is an antiferromagnetic mixed valence cuprate where trilayers of edge -sharing Cu(II)O (3d9) are sandwiched in between planes of Cu(I) (3d10) ions, with Li stochastically substituting Cu(II). Angle resolved photoemission spectroscopy (ARPES) and de ...

Amer Physical Soc2024

Orbital-selective metal skin induced by alkali-metal-dosing Mott-insulating Ca2RuO4

Henrik Moodysson Rønnow, Gianmarco Gatti

Doped Mott insulators are the starting point for interesting physics such as high temperature superconductivity and quantum spin liquids. For multi-band Mott insulators, orbital selective ground states have been envisioned. However, orbital selective metal ...

Nature Portfolio2023

Nanoscale-Resolved Surface-to-Bulk Electron Transport in CsPbBr3 Perovskite

Marco Grioni, Majed Chergui, Alberto Crepaldi, Nicola Marzari, Nicola Colonna, Gianmarco Gatti, Serhii Polishchuk, Michele Puppin

Describing the nanoscale charge carrier transport at surfaces and interfaces is fundamental for designing highperformance optoelectronic devices. To achieve this, we employ time-and angle-resolved photoelectron spectroscopy with ultraviolet pump and extrem ...

AMER CHEMICAL SOC2022

Origin of large magnetoresistance in the topological nonsymmorphic semimetal TaSe3

Jean-Philippe Ansermet, Helmuth Berger, Oleg Yazyev, Alberto Crepaldi, Gabriel Albert Autes, Gianmarco Gatti, Daniel Gosalbez Martinez, Quansheng Wu, Michele Puppin, Shengnan Zhang

TaSe3 is a layered van der Waals semimetal with several inverted band gaps throughout the entire Brillouin zone and nontrivial Z(2) topological indices, which place it at the boundary between a strong and a weak topological phase. Our transport experiments ...

2021

Hidden bulk and surface effects in the spin polarization of the nodal-line semimetal ZrSiTe

Helmuth Berger, Marco Grioni, Arnaud Magrez, Oleg Yazyev, Alberto Crepaldi, Mauro Fanciulli, Gianmarco Gatti, Daniel Gosalbez Martinez, Silvan Dino Marcos Roth

Local inversion symmetry breaking in centrosymmetric materials can lead to large spin polarization of the electronic band structure in separate sectors of the unit cell. Here, the authors reveal such hidden spin polarisation in ZrSiTe using spin and angle ...

NATURE RESEARCH2021

Radial Spin Texture of the Weyl Fermions in Chiral Tellurium

Philippe Bugnon, Marco Grioni, Majed Chergui, Oleg Yazyev, Luca Moreschini, Henrik Moodysson Rønnow, Alberto Crepaldi, Simon Karl Moser, Luc Testa, Mauro Fanciulli, Edoardo Martino, Gianmarco Gatti, Daniel Gosalbez Martinez, Silvan Dino Marcos Roth, Serhii Polishchuk, Michele Puppin

Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of a chiral crystal. We have studied by spin- and angle-resolved photoelectron spectroscopy its unconventional ...

AMER PHYSICAL SOC2020

Evidence of Large Polarons in Photoemission Band Mapping of the Perovskite Semiconductor CsPbBr3

Marco Grioni, Majed Chergui, Alberto Crepaldi, Nicola Marzari, Nicola Colonna, Gianmarco Gatti, Serhii Polishchuk, Thomas Roland Barillot, Michele Puppin, Riccardo De Gennaro, Matthias Wolf

Lead-halide perovskite (LHP) semiconductors are emergent optoelectronic materials with outstanding transport properties which are not yet fully understood. We find signatures of large polaron formation in the electronic structure of the inorganic LHP CsPbB ...

AMER PHYSICAL SOC2020

Light-Induced Renormalization of the Dirac Quasiparticles in the Nodal-Line Semimetal ZrSiSe

Helmuth Berger, Philippe Bugnon, Marco Grioni, Majed Chergui, Arnaud Magrez, Luca Moreschini, Alberto Crepaldi, Simon Karl Moser, Gianmarco Gatti, Serhii Polishchuk, Michele Puppin

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correla ...

2020

Experimental studies of the equilibrium and out-of-equilibrium electronic structure of non-symmorphic topological materials

Gianmarco Gatti

Symmetry and topology are fundamental properties of nature. Mathematics provides us with a general framework to understand these concepts. On one side, symmetry describes the invariance properties of an object for specific transformations. On the other sid ...

EPFL2020

Unveiling the electronic transformations in the semi-metallic correlated-electron transitional oxide Mo8O23

Marco Grioni, Gianmarco Gatti

Mo8O23 is a low-dimensional chemically robust transition metal oxide coming from a prospective family of functional materials, MoO3-x, ranging from a wide gap insulator (x = 0) to a metal (x = 1). The large number of stoichometric compounds with intermedia ...

Nature Research2019

Photocarrier-induced band-gap renormalization and ultrafast charge dynamics in black phosphorus

Marco Grioni, Majed Chergui, Steven Roth, Alberto Crepaldi, Gianmarco Gatti, Michele Puppin

With its tunable band-gap and its unique optical and electronic properties black phosphorus (BP) opens exciting opportunities for optoelectronic nanotechnology. The band-gap extends from the visible to the mid-infrared spectral range, as a function of samp ...

2019

Orbitally selective breakdown of Fermi liquid quasiparticles in Ca1.8Sr0.2RuO4

Marco Grioni, Johan Juul Chang, Gianmarco Gatti

We present a comprehensive angle-resolved photoemission spectroscopy study of Ca1.8Sr0.2RuO4. Four distinct bands are revealed and along the Ru-O bond direction their orbital characters are identified through a light polarization analysis and comparison to ...

AMER PHYSICAL SOC2019

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Marco Grioni, Henrik Moodysson Rønnow, Simon Karl Moser, Johan Juul Chang, Claudia Giuseppina Fatuzzo, Gianmarco Gatti

A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic str ...

Nature Research2017

Harmonium: An Ultrafast Vacuum Ultraviolet Facility

Marco Grioni, Marcel Drabbels, Majed Chergui, Frank van Mourik, Christopher Alexander Arrell, Alberto Crepaldi, José Javier Pancracio Ojeda Andara, Andrew Daniel Bonnar Clark, Gianmarco Gatti, Luca Longetti, Silvan Dino Marcos Roth

Harmonium is a vacuum ultraviolet (VUV) photon source built within the Lausanne Centre for Ultrafast Science (LACUS). Utilising high harmonic generation, photons from 20-110 eV are available to conduct steady-state or ultrafast photoelectron and photoion s ...

Swiss Chemical Soc2017

Time-resolved ARPES at LACUS: Band Structure and Ultrafast Electron Dynamics of Solids

Helmuth Berger, Philippe Bugnon, Marco Grioni, Majed Chergui, Frank van Mourik, Arnaud Magrez, Christopher Alexander Arrell, Alberto Crepaldi, José Javier Pancracio Ojeda Andara, Gianmarco Gatti, Silvan Dino Marcos Roth

The manipulation of the electronic properties of solids by light is an exciting goal, which requires knowledge of the electronic structure with energy, momentum and temporal resolution. Time- and angle-resolved photoemission spectroscopy (tr-ARPES) is the ...

2017

Electronic Phase Separation and Dramatic Inverse Band Renormalization in the Mixed-Valence Cuprate LiCu2O2

Helmuth Berger, Philippe Bugnon, Marco Grioni, Arnaud Magrez, Luca Moreschini, Simon Karl Moser, Gianmarco Gatti

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu2O2, a mixed-valence cuprate where planes of Cu(I) (3d(10)) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d(9)) chains. We find ...

Amer Physical Soc2017