High temperature superconductors and Mott
insulators far from equilibrium conditions
L. Perfetti, Laboratoire des Solides Irradiés
High temperature superconductors
Optimally doped Bi2Sr2CaCu2O8+δ superconductor below 90 K
Zailan Zhang
Cristian Piovera
T*
T
crossover
To
100
AF
0
Fluctuations
Tc
SC
0.15
doping
Macroscopic quantum matter due to finite pairing amplitude
Meissner Effect, zero resistance, single particle gap
Linear susceptibilities follow to a single temperature scale Tc
Paraconductivity
Fluctuations above Tc
long range order below Tc
OP Bi2Sr2CaCu2O8+δ
Y. Wang, Phys. Rev. Lett. 95, 247002
(2005)
F. Rullier-Albenque, Phys. Rev. B 84,
014522 (2011)
Diamagnetism
Doping
Strongly driven superconductors:
pump with 1.5 photons
Are some superconducting correlations more robust
than others?
• Supercurrents, Tr-THz
• single particle gap, Tr-ARPES
• Scattering of low energy excitations, Tr-ARPES
Multiple energy scales
Gap (meV)
d-wave pairing
in reciprocal space
Angle °
disorder in direct space
THz measurements of
superfluid density
R. Kaindl, Phys. Rev. B 72, 060510 (2005)
M. A. Carnahan, Physica C 408, 709 (2004)
The superconducing gap in the photoexcited state
C. L. Smallwood, Science 336, 1137 (2012)
C. L. Smallwood, Phys. Rev. B 89, 155126 (2014)
Gap (meV)
FEMTOARPES
Angle °
EDCs at KF above Tc
Opening of superconducting
gap ∆ = 20 meV by lowering
the temperature below Tc
Simmetrized EDCs at KF
below Tc
EDCs at KF below Tc
Photoexcitation and
thermal fluctuations
are comparable
Gap Collapse as a
function of fluence
Dynamics of the superconducting gap
φ =23°
Wavevector (1/nm)
3 ps
The superconducting gap is more robust towards the antinodes
Gap (meV)
Supercurrents and near nodal gap follow similar behaviour
40 µJ/cm2
30 µJ/cm2
Angle °
Scattering of low energy excitations, Tr-ARPES
C. Piovera Phys Rev B 91, 224509 (2015)
Below Tc the dissipation of low energy
quasiparticles is blocked
Persistence of superconducting correlations up to
high fluence
Fast dissipation channel appears at 60 µJ/cm2
and saturates at roughly 200 µJ/cm2
Dissipation of low energy electrons in the nodal direction
S. L. Yang, Phys. Rev. Lett. 114, 24 7001 (2015)
Fluence and momentum dependence of the gap collape related to
the uncoventional pairing in high temperature superconductors
Gap (meV)
d-wave
Angle °
Analogy to high magnetic fields
G. Grissonnanque,
Nature Comm. 5, 3280 (2014)
Reduction of superfluid density in the mixed phase
R. Mallozzi, Phys. Rev. Lett. 81, 1485 (1998)
Quenched disorder implies local variations of paring amplitudes
Non-homogeous break-down of rigidity upon photoexcitation
Randomization of condensate phase
Sr2IrO4 Mott insulator with large spin-orbit coupling
Quasi two dimensional structure
Cristian Piovera
Veronique Brouet
C. Piovera, Phys. Rev. B 93, 241114(R) (2016)
V. Brouet, Phys Rev B 92, 081117(R) (2015)
Magnetic transition at 245 Kelvin, strong antiferromagnetic
fluctuations above the Neel temperature
Analogies with cuprates: superconductivity in doped
compounds?
Electronic properties of Sr2IrO4
B. J. Kim, Phys. Rev. Lett. 101, 076402 (2008)
Dispersion of electronic states
Jeff = 1/2 and Jeff = 3/2
clearly identified
Mott gap
Large dispersion due to
antiferromantic correlations
V. Brouet, Phys Rev B 92, 081117(R)
(2015)
Doping with acceptors and donors
B. H. Kim, Phys. Rev. Lett. 109, 167205 (2012)
Photoinduced mid-gap states
Doublons-holons pairs are unstable
Similar to cuprates
H. Okamoto, Phys .Rev. B 83,
125102 (2011)
Nd2CuO4
Sudden relaxation of
electrons above the
chemical potential
Two steps dynamics
of midgap states
Delays (fs)
No doping dependence
C. Piovera, Phys. Rev. B 93, 241114(R) (2016)
Possible mechanisms of ulltrafast relaxation
Oxygen inhomogenities leading to local gap collapse
Y. Okada, Nature mat. 12, 707 (2013)
Conclusions
•Hierarchy of superconducting correlations out of equilibrium:
phase coherence, superconducting gap, quasiparticle scattering
Superconducting correlations persisting to high pumping fluence
• Instability of doublon-holons pairs in Strontium Iridate:
Sudden generation and ultrafast decay of mid-gap states:
Possible role of Oxygen inhomogeinity and strong coupling to
collective excitations.
Collaborators
C. Piovera
Laboratoire des Solides Irradiés, Ecole Polytechnique
Z. Zhang, M. d’Astuto
UPMC, Université Paris 6
V. Brouet, E. Papalazarou, M. Marsi, H. Raffy
Laboratoire de Physique des Solides, Université Paris-Sud
Temperature dependence of the speudogap in Bi-2201
N. Hashimoto Nature Phys. (2014)
Temperature (K)
Bi-2201 shows the fast decay even at low temperature
Blocking of optical phonon emission is not due to the
speudogap