| 1. |
- Ghosh, Anirudha, et al.
(author)
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Exotic magnetic and electronic properties of layered CrI3 single crystals under high pressure
- 2022
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In: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 105:8
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Journal article (peer-reviewed)abstract
- Through advanced experimental techniques on CrI3 single crystals, we derive a pressure-temperature phase diagram. We find that T-c increases to similar to 66 K with pressure up to similar to 3 GPa followed by a decrease to similar to 10 K at 21.2 GPa. The experimental results are reproduced by theoretical calculations based on density functional theory where electron-electron interactions are treated by a static on-site Hubbard U on Cr 3d orbitals. The origin of the pressure-induced reduction of the ordering temperature is associated with a decrease in the calculated bond angle, from 95 degrees at ambient pressure to similar to 85 degrees at 25 GPa. Above 22 GPa, experiment and theory jointly point to the idea that the ferromagnetically ordered state is destroyed, giving rise first to a complex, unknown magnetic configuration, and at sufficiently high pressures a pure antiferromagnetic configuration. This sequence of transitions in the magnetism is accompanied by a well-detected pressure-induced semiconductor-to-metal phase transition that is revealed by both high-pressure resistivity measurements and ab initio theory.
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| 2. |
- Ghosh, Anirudha, et al.
(author)
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Magnetic circular dichroism in the dd excitation in the van der Waals magnet CrI3 probed by resonant inelastic x-ray scattering
- 2023
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In: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 107:11
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Journal article (peer-reviewed)abstract
- We report on a combined experimental and theoretical study on CrI3 single crystals by employing the polarization dependence of resonant inelastic x-ray scattering (RIXS). Our investigations reveal multiple Cr 3d orbital splitting (dd excitations) as well as magnetic dichroism (MD) in the RIXS spectra. The dd excitation energies are similar on the two sides of the ferromagnetic transition temperature, T-C similar to 61 K, although MD in RIXS is predominant at 0.4 T magnetic field below TC. This demonstrates that the ferromagnetic superexchange interaction that is responsible for the interatomic exchange field is vanishingly small compared with the local exchange field that comes from exchange and correlation interaction among the interacting Cr 3d orbitals. The recorded RIXS spectra reported here reveal clearly resolved Cr 3d intraorbital dd excitations that represent transitions between electronic levels that are heavily influenced by dynamic correlations and multiconfiguration effects. Our calculations taking into account the Cr 3d hybridization with the ligand valence states and the full multiplet structure due to intra-atomic and crystal field interactions in Oh and D3d symmetry clearly reproduced the dichroic trend in experimental RIXS spectra.
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| 3. |
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| 4. |
- John Mukkattukavil, D., et al.
(author)
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Resonant inelastic soft x-ray scattering on LaPt 2 Si 2
- 2022
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In: Journal of physics. Condensed matter : an Institute of Physics journal. - 1361-648X .- 0953-8984. ; 34:32
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Journal article (peer-reviewed)abstract
- X-ray absorption and resonant inelastic x-ray scattering spectra of LaPt2Si2single crystal at the Si 2pand La 4dedges are presented. The data are interpreted in terms of density functional theory, showing that the Si spectra can be described in terms of Sisanddlocal partial density of states (LPDOS), and the La spectra are due to quasi-atomic local 4fexcitations. Calculations show that Ptd-LPDOS dominates the occupied states, and a sharp localized Lafstate is found in the unoccupied states, in line with the observations.
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| 5. |
- John Mukkattukavil, Deepak, et al.
(author)
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Resonant inelastic soft x-ray scattering on LaPt2Si2
- 2022
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In: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 34:32, s. 324003-
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Journal article (peer-reviewed)abstract
- X-ray absorption and resonant inelastic x-ray scattering spectra of LaPt2Si2 single crystal at the Si 2p and La 4d edges are presented. The data are interpreted in terms of density functional theory, showing that the Si spectra can be described in terms of Si s and d local partial density of states (LPDOS), and the La spectra are due to quasi-atomic local 4f excitations. Calculations show that Pt d-LPDOS dominates the occupied states, and a sharp localized La f state is found in the unoccupied states, in line with the observations.
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| 6. |
- Mukkattukavil, Deepak John, 1993-, et al.
(author)
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Resonant inelastic soft x-ray scattering on LaPt2Si2
- 2022
-
In: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 34:32
-
Journal article (peer-reviewed)abstract
- X-ray absorption and resonant inelastic x-ray scattering spectra of LaPt2Si2 single crystal at the Si 2p and La 4d edges are presented. The data are interpreted in terms of density functional theory, showing that the Si spectra can be described in terms of Si s and d local partial density of states (LPDOS), and the La spectra are due to quasi-atomic local 4f excitations. Calculations show that Pt d-LPDOS dominates the occupied states, and a sharp localized La f state is found in the unoccupied states, in line with the observations.
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| 7. |
- Sahu, Aditya K., et al.
(author)
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Understanding blue shift of the longitudinal surface plasmon resonance during growth of gold nanorods
- 2021
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In: NANO EXPRESS. - : Institute of Physics Publishing (IOPP). - 2632-959X. ; 2:1
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Journal article (peer-reviewed)abstract
- We have investigated in detail the growth dynamics of gold nanorods with various aspect ratios in different surrounding environments. Surprisingly, a blue shift in the temporal evolution of colloidal gold nanorods in aqueous medium has been observed during the growth of nanorods by UV-visible absorption spectroscopy. The longitudinal surface plasmon resonance peak evolves as soon as the nanorods start to grow from spheres, and the system undergoes a blue shift in the absorption spectra. Although a red-shift is expected as a natural phenomenon during the growth process of all nano-systems, our blue shift observation is regarded as a consequence of competition between the parameters of growth solution and actual growth of nanorods. The growth of nanorods contributes to the red-shift which is hidden under the dominating contribution of the growth solution responsible for the observed massive blue shift.
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| 8. |
- Söderström, Johan, et al.
(author)
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Parity violation in resonant inelastic soft x-ray scattering at entangled core holes
- 2024
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In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 10:7, s. 3114-
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Journal article (peer-reviewed)abstract
- Resonant inelastic x-ray scattering (RIXS) is a major method for investigation of electronic structure and dynamics, with applications ranging from basic atomic physics to materials science. In RIXS applied to inversion-symmetric systems, it has generally been accepted that strict parity selectivity applies in the sub-kilo-electron volt region. In contrast, we show that the parity selection rule is violated in the RIXS spectra of the free homonuclear diatomic O2 molecule. By analyzing the spectral dependence on scattering angle, we demonstrate that the violation is due to the phase difference in coherent scattering at the two atomic sites, in analogy with Young's double-slit experiment. The result also implies that the interpretation of x-ray absorption spectra for inversion symmetric molecules in this energy range must be revised.
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| 9. |
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- 2019
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Journal article (peer-reviewed)
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