A5102949788- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- High-pressure geophysics and materials
- Magnetic properties of thin films
- X-ray Diffraction in Crystallography
- Multiferroics and related materials
- Crystal Structures and Properties
- Geophysical and Geoelectrical Methods
- Theoretical and Computational Physics
- Photonic Crystals and Applications
- Rare-earth and actinide compounds
- Magneto-Optical Properties and Applications
- Advanced NMR Techniques and Applications
- Graphene research and applications
University of Connecticut
2023
University of Geneva
2010-2012
Stanford Synchrotron Radiation Lightsource
2006-2010
We study Na2IrO3 by ARPES, optics, and band structure calculations in the local-density approximation (LDA). The weak dispersion of Ir 5d-t2g manifold highlights importance structural distortions spin-orbit coupling (SO) driving system closer to a Mott transition. detect an insulating gap {\Delta}_gap = 340 meV which, at variance with Slater-type description, is already open 300 K does not show significant temperature dependence even across T_N ~ 15 K. An LDA analysis inclusion SO Coulomb...
Using high-resolution resonant inelastic x-ray scattering (RIXS), we performed a momentum-resolved study of magnetic excitations in the model spin-1/2 2D antiferromagnetic insulator Sr_2CuCl_2O_2. We identify both single-spin-wave feature and multi-magnon continuum, show that X-ray polarization can be used to distinguish these two contributions cross-section. The spin-waves display large (70 meV) dispersion between zone-boundary points ($\pi$,0) ($\pi$/2,$\pi$/2). Employing an extended...
We present a resonant inelastic scattering (RIXS) study using of ${\text{CuB}}_{2}{\text{O}}_{4}$, which contains lattice ${\text{CuO}}_{4}$ plaquettes electronically isolated by ${\text{B}}^{+3}$ ions. The observed $\text{Cu}\text{ }K$-edge spectra show small number well-separated features, and the simple electronic structure ${\text{CuB}}_{2}{\text{O}}_{4}$ allows us to explore RIXS phenomenology. find low-energy feature that cannot be attributed same charge-transfer excitation discussed...
We present a detailed Cu $K$-edge resonant inelastic x-ray scattering (RIXS) study of the Mott insulator ${\mathrm{La}}_{2}\mathrm{Cu}{\mathrm{O}}_{4}$ in $1--7\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ energy loss range. As initially found for high-temperature superconductor $\mathrm{Hg}{\mathrm{Ba}}_{2}\mathrm{Cu}{\mathrm{O}}_{4+\ensuremath{\delta}}$, spectra exhibit multiplet weakly dispersive electron-hole excitations, which are revealed by utilizing subtle dependence cross section on...
We present a study of the charge-transfer excitations in undoped ${\text{Nd}}_{2}{\text{CuO}}_{4}$ using resonant inelastic x-ray scattering (RIXS) at $\text{Cu}\text{ }K$-edge. At Brillouin zone center, azimuthal scans that rotate incident-photon polarization within ${\text{CuO}}_{2}$ planes reveal weak fourfold oscillations. A comparison spectra taken different zones reveals spectral weight decrease high-energy loss from forward- to back-scattering. show these are scattered-photon effects...
In this paper, we discuss our recent Cu K-edge resonant inelastic x-ray scattering (RIXS) results for CuB2O4, a model system consisting of electronically isolated CuO4 plaquettes, which exhibits anomalies in the incident photon energy dependence that are not captured by electron-only models. We show these anomalous features can be qualitatively described extending considerations to include lattice degrees freedom. Our findings have important general implications interpretation RIXS...
The halide perovskite TiF 3 , renowned for its intricate interplay between structure, electronic correlations, magnetism, and thermal expansion, is investigated. Despite simple understanding low‐temperature magnetic behavior has been a challenge. Previous theories propose antiferromagnetic ordering. In contrast, experimental signatures an ordered state are absent down to 10 K. current study successfully reevaluated the theoretical modeling of unveiling significance strong correlations as key...
Received 23 September 2011DOI:https://doi.org/10.1103/PhysRevLett.107.149903© 2011 American Physical Society
We investigate the halide perovskite TiF$_3$, renowned for its intricate interplay between structure, electronic correlations, magnetism, and thermal expansion. Despite simple understanding low-temperature magnetic behavior has been a challenge. Previous theories proposed antiferromagnetic ordering. In contrast, experimental signatures an ordered state are absent down to 10~K. Our current study successfully reevaluated theoretical modeling of unveiling significance strong correlations as key...
Received 30 September 2009DOI:https://doi.org/10.1103/PhysRevB.80.139901©2009 American Physical Society