


2019-01-18
ION HANCU
ION HANCU

2019-01-29
MARIA MAFFEI
MARIA MAFFEI

2019-02-13
BORIS BOURDONCLE
BORIS BOURDONCLE

2019-02-15
JORDI MORALES DALMAU
JORDI MORALES DALMAU

2019-02-22
FRANCESCO RICCI
FRANCESCO RICCI

2019-03-06
CLARA GREGORI
CLARA GREGORI

2019-03-26
ALEXIA SALAVRAKOS
ALEXIA SALAVRAKOS

2019-04-12
SENAIDA HERNANDEZ SANTANA
SENAIDA HERNANDEZ SANTANA

2019-04-15
DAVID RAVENTÓS RIBERA
DAVID RAVENTÓS RIBERA

2019-04-16
PETER SCHMIDT
PETER SCHMIDT

2019-04-29
CALLUM O’DONNELL
CALLUM O’DONNELL

2019-05-02
LUCIANA VIDAS
LUCIANA VIDAS

2019-05-03
HANYU YE
HANYU YE

2019-05-10
TANJA DRAGOJEVIC
TANJA DRAGOJEVIC

2019-05-17
FLAVIO BACCARI
FLAVIO BACCARI

2019-06-04
MARTINA GIOVANNELLA
MARTINA GIOVANNELLA

2019-07-02
OZLEM YAVAS
OZLEM YAVAS

2019-07-03
ALESSANDRO SERI
ALESSANDRO SERI

2019-07-11
RENWEN YU
RENWEN YU

2019-09-06
ALEXANDER BLOCK
ALEXANDER BLOCK

2019-10-04
MARCO PAGLIAZZI
MARCO PAGLIAZZI

2019-10-07
RINU MANIYARA
RINU MANIYARA

2019-10-15
ALEJANDRO POZAS-KERSTJENS
ALEJANDRO POZAS-KERSTJENS
The Insulator-Metal Phase Transition in VO2 Measured at Nanometer Length Scales and Femtosecond Time Scales


LUCIANA VIDAS
May 2nd, 2019
LUCIANA VIDAS
Ultrafast Dynamics in Quantum Solids
ICFO-The Institute of Photonic Sciences
The physics of transition-metal oxides presents a challenge to our current understanding of condensed matter physics. The main difficulty arises from a competition between electron-electron and electron-phonon interactions to dictate the properties of these complex materials. This issue is particularly apparent in vanadium dioxide, which undergoes an electronic and structural phase transition close to room temperature. Despite more than 50 years of research, the origin of the transformation is still actively debated, with contradictory interpretations often reported. The main goal of this thesis is to re-evaluate the phase transition in VO2 with a combination of new experimental techniques, ranging from the midinfrared to hard x-rays, that can probe the transformation at nanometer length scales and femtosecond time-scales. This allows to disentangle the roles of phase separation, laser-induced heat, and electron and phonon dynamics to the insulator-metal transition. The results from these experiments provide a unified and new picture of the nature of this process, both in and out of equilibrium, in which the electron-phonon interactions are the main driving mechanism. Furthermore, the new techniques and analysis presented here for VO2 can be applied to the study of other controversial complex materials that exhibit remarkable properties, and answer thereby some of the key outstanding questions in condensed matter physics.
Thursday May 2, 11:00. ICFO Auditorium
Thesis Advisor: Prof Dr Simon Wall
ICFO-The Institute of Photonic Sciences
The physics of transition-metal oxides presents a challenge to our current understanding of condensed matter physics. The main difficulty arises from a competition between electron-electron and electron-phonon interactions to dictate the properties of these complex materials. This issue is particularly apparent in vanadium dioxide, which undergoes an electronic and structural phase transition close to room temperature. Despite more than 50 years of research, the origin of the transformation is still actively debated, with contradictory interpretations often reported. The main goal of this thesis is to re-evaluate the phase transition in VO2 with a combination of new experimental techniques, ranging from the midinfrared to hard x-rays, that can probe the transformation at nanometer length scales and femtosecond time-scales. This allows to disentangle the roles of phase separation, laser-induced heat, and electron and phonon dynamics to the insulator-metal transition. The results from these experiments provide a unified and new picture of the nature of this process, both in and out of equilibrium, in which the electron-phonon interactions are the main driving mechanism. Furthermore, the new techniques and analysis presented here for VO2 can be applied to the study of other controversial complex materials that exhibit remarkable properties, and answer thereby some of the key outstanding questions in condensed matter physics.
Thursday May 2, 11:00. ICFO Auditorium
Thesis Advisor: Prof Dr Simon Wall