Concept

Paire de Cooper

Publications associées (106)

Dressed excitons within an incoherent electron gas: Observation of a Mollow triplet and an Autler-Townes doublet

Benoît Marie Joseph Deveaud, Jean Berney, Marcia Portella Oberli

We demonstrate that the interaction between excitons and a sea of incoherent electrons does not preclude excitons dressing by light. We investigate if exciton-electron scattering plays some inhibiting role in the coherent light-exciton coupling by measurin ...

2008

Density-functional theory study of Au, Ag and Cu defects in germanium

Alexandra Sarabando de Carvalho

Gold, silver and copper defects in germanium are modeled using density functional theory. The structures and electrical properties of the substitutional metals are calculated in excellent agreement with experiment. Interstitial Au, Ag and Cu are found to b ...

2008

Matthiessen's rule in MgB2: Resistivity and T-c as a function of point defect concentration

László Forró, Richard Gaal, Balazs Sipos, Janusz Andrzej Karpinski, Neven Barisic

We present the results of a systematic study of the temperature-dependent resistivity and of T-c of a single crystal MgB2 sample as a function of point defect concentration. We have found linear, albeit weak, correlation between the decreasing superconduct ...

2007

Two energy scales in the spin excitations of the high-temperature superconductor La2-xSrxCuO4

Henrik Moodysson Rønnow

The excitations responsible for producing high-temperature superconductivity in the copper oxides have yet to be identified. Two promising candidates are collective spin excitations and phonons(1). A recent argument against spin excitations is based on the ...

Nature Publishing Group2007

Phonon anharmonicities in graphite and graphene

Nicola Marzari

We determine from first principles the finite-temperature properties-linewidths, line shifts, and lifetimes-of the key vibrational modes that dominate inelastic losses in graphitic materials. In graphite, the phonon linewidth of the Raman-active E-2g mode ...

2007

Charged excitons in modulation-doped quantum wires

Elyahou Kapon, Benjamin Dwir, Marc-André Dupertuis, Daniel Oberli, Nicolas Moret

We report on the observation of negatively- and positively-charged excitons in the photoluminescence spectra of V-groove quantum wires. The. charged exciton binding energy increases with the strength of the quantum confinement. We demonstrate that fluctuat ...

American Institute of Physics2005

Enhancement of the binding energy of charged excitons in disordered quantum wires

Elyahou Kapon, Benjamin Dwir, Marc-André Dupertuis, Daniel Oberli, Klaus Leifer, Nicolas Moret

Negatively and positively charged excitons are identified in the spatially resolved photoluminescence spectra of quantum wires. We demonstrate that charged excitons are weakly localized in disordered quantum wires. As a consequence, the enhancement of the ...

2005

Strong electron-electron and electron-phonon interactions in one- and two-dimensional solids

Marco Grioni, Helmuth Berger, Luca Perfetti

We discuss the spectral signatures of strong electronic correlations and electron-phonon interactions in two representative low-dimensional systems. In the 2D compound 1T-TaSe2 a charge-density-wave (CDW) induces a narrowing of the conduction band, which t ...

Elsevier2004

Observation of charged excitons in V-groove quantum wires

Elyahou Kapon, Benjamin Dwir, Marc-André Dupertuis, Daniel Oberli

We report on the observation of negatively and positively charged excitons in the photoluminescence spectra of V-groove quantum wires. The charged exciton binding energy increases with the strength of the quantum confinement. We demonstrate that the charge ...

V C H Publishers, Suite 909, 220 E 23Rd St, New York, Ny 10010 Usa2004

Electronic and vibrational properties of the low-dimensional perovskites Sr1-yLayNbO3.5-x

Marco Grioni

By angle-resolved photoemission spectroscopy and polarization-dependent infrared reflectivity measurements the electronic and vibrational properties of the low-dimensional perovskites Sr1-yLayNbO3.5-x were studied along different crystal directions. The el ...

2004

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