Publications by Luca Perfetti | EPFL Graph Search

BROKEN-SYMMETRY STATES AT SURFACES: THE (tr)ARPES VIEW

We discuss recent high-resolution angle-resolved photoemission (ARPES) and time-resolved ARPES experiments on selected surfaces which illustrate the formation of broken-symmetry ground states of very different nature: i) a Mott insulator in the layered dic ...

2009

Femtosecond dynamics of electronic states in the Mott insulator 1T-TaS2 by time resolved photoelectron spectroscopy

Helmuth Berger, Luca Perfetti, Matthias Wolf

Photoexcitation of the Mott insulator 1T-TaS2 by an intense laser pulse leads to an ultrafast transition toward a gapless phase. Besides the collapse of the electronic gap, the sudden excitation of the charge density wave (CDW) mode results in periodic osc ...

2008

Photoemission as a probe of coexisting and conflicting periodicities in low-dimensional solids

Helmuth Berger, Marco Grioni, Luca Perfetti, Christian Reinhard Ast, Daniela Pacilè

When two different periodic potentials are present at the same time in a solid, the electron wavefunctions must conform to the resulting overall periodicity. It is the case of the broken-symmetry phases which are often observed in low-dimensional systems. ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2005

Unexpected periodicity in the quasi-two-dimensional Mott insulator 1T-TaS2 revealed by angle-resolved photoemission

Thomas Gloor, Helmuth Berger, Marco Grioni, Luca Perfetti, Frédéric Mila

High-resolution angle-resolved photoemission data from the insulating phase of the charge-density-wave (CDW) material 1T-TaS2 reveal the backfolding of the electronic bands associated with the CDW superlattice, but also an additional, unexpected periodicit ...

2005

Mott phase at the surface of 1T-TaSe2 observed by scanning tunneling microscopy

Helmuth Berger, Marco Grioni, Luca Perfetti

In this Letter we report the observation, by scanning tunneling microscopy, of a Mott metal to insulator transition at the surface of 1T-TaSe2. Our spectroscopic data compare considerably well with previous angle-resolved photoemission spectroscopy measure ...

American Physical Society2005

Angle resolved photoelectron spectroscopy on strongly correlated electron-phonon systems

Luca Perfetti

EPFL2002