Publications by Dirk Van der Marel

Resonant Inelastic X-Ray Scattering Study of Electron-Exciton Coupling in High-T-c Cuprates

Christophe Berthod, Fabrizio Carbone, Ivan Madan, Yi Tseng, Francesco Barantani, Thorsten Schmitt, Dirk Van der Marel

Explaining the mechanism of superconductivity in the high-T-c cuprates requires an understanding of what causes electrons to form Cooper pairs. Pairing can be mediated by phonons, the screened Coulomb force, spin or charge fluctuations, excitons, or by a c ...

American Physical Society2022

Optical properties of BiTeBr and BiTeCl

Helmuth Berger, Philippe Bugnon, Arnaud Magrez, Ana Akrap, Dirk Van der Marel

We present a comparative study of the optical properties-reflectance, transmission, and optical conductivity- and Raman spectra of two layered bismuth-tellurohalides BiTeBr and BiTeCl at 300 and 5 K, for light polarized in the a-b planes. Despite different ...

Amer Physical Soc2014

Infrared- and Raman-Spectroscopy Measurements of a Transition in the Crystal Structure and a Closing of the Energy Gap of BiTeI under Pressure

Oleg Yazyev, Ana Akrap, Gabriel Albert Autes, Dirk Van der Marel

BiTeI is a giant Rashba spin splitting system, in which a noncentrosymmetric topological phase has recently been suggested to appear under high pressure. We investigated the optical properties of this compound, reflectivity and transmission, under pressure ...

American Physical Society2014

Infrared Conductivity of Elemental Bismuth under Pressure: Evidence for an Avoided Lifshitz-Type Semimetal-Semiconductor Transition

László Forró, Dirk Van der Marel

The application of pressure to elemental bismuth reduces its conduction-valence band overlap, and results in a semimetal-semiconductor (SMSC) transition around 25 kbar. This transition is nominally of the topological "Lifshitz'' Fermi surface variety, but ...

American Physical Society2010

Measurement of Magnetic Excitations in the Two-Dimensional Antiferromagnetic Sr2CuO2Cl2 Insulator Using Resonant X-Ray Scattering: Evidence for Extended Interactions

Helmuth Berger, Marco Grioni, Bastien Dalla Piazza, Ping-Hui Lin, Peng Xu, Henrik Moodysson Rønnow, Marco Guarise, Thorsten Schmitt, Dirk Van der Marel

We measured the momentum dependence of magnetic excitations in the model spin-1/2 2D antiferromagnetic insulator Sr2CuO2Cl2 (SCOC). We identify a single-spin-wave feature and a multimagnon continuum, with different polarization dependences. The spin waves ...

American Physical Society2010

Evidence for core-hole-mediated inelastic x-ray scattering from metallic Fe1.087Te

Marco Grioni, Ping-Hui Lin, Henrik Moodysson Rønnow, Marco Guarise, Thorsten Schmitt, Dirk Van der Marel

We present a detailed analysis of resonant inelastic x-ray scattering from Fe1.087Te with unprecedented energy resolution. In contrast to the sharp peaks typically seen in insulating systems at the transition-metal L-3 edge, we observe spectra which show d ...

2010

Electron-phonon interaction and charge carrier mass enhancement in SrTiO3

Claudio Grimaldi, Dirk Van der Marel

We report a comprehensive THz, infrared and optical study of Nb-doped SrTiO3 as well as dc conductivity and Hall effect measurements. Our THz spectra at 7 K show the presence of an unusually narrow (< 2 meV) Drude peak. For all carrier concentrations the D ...

2008