Changhee Sohn

Temperature evolution of itinerant ferromagnetism in SrRuO3 probed by optical spectroscopy.

The temperature (T) dependence of the optical conductivity spectra σ(ω) of a single crystal SrRuO(3) thin film is studied over a T range from 5 to 450 K. We observed significant T dependence of the spectral weights of the charge transfer and interband d-d transitions across the ferromagnetic Curie temperature (T(c) ∼ 150 K). Such T dependence was attributed to the increase in the Ru spin moment, which is consistent with the results of density functional theory calculations. T scans of σ(Ω,T) at fixed frequencies Ω reveal a clear T(2) dependence below T(c), demonstrating that the Stoner mechanism is involved in the evolution of the electronic structure. In addition, σ(Ω,T) continues to evolve at temperatures above T(c), indicating that the local spin moment persists in the paramagnetic state. This suggests that SrRuO(3) is an intriguing oxide system with itinerant ferromagnetism.

Phonon-assisted optical excitation in the narrow bandgap Mott insulator Sr3Ir2O7

We examined the temperature (T) evolution of the optical conductivity spectra of Sr

Optical Spectroscopic Studies of the Metal-Insulator Transition Driven by All-In-All-Out Magnetic Ordering in 5d Pyrochlore Cd(2)Os(2)O(7).

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Electronic structure and insulating gap in epitaxial VO2 polymorphs

Ir

Two-magnon scattering in the 5d all-in-all-out pyrochlore magnet Cd2Os2O7

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Strong Spin-Phonon Coupling Mediated by Single Ion Anisotropy in the All-In–All-Out Pyrochlore Magnet Cd2Os2O7

O

Charge Transfer in Iridate-Manganite Superlattices

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X-ray Absorption Spectroscopy Study of the Effect of Rh doping in Sr2IrO4

over a wide range of 10-400 K. The system was barely insulating, exhibiting a small indirect bandgap of

Stabilization of ferromagnetic ordering in cobaltite double perovskites of La₂CoIrO₆ and La₂CoPtO₆.

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Nanoscale Control of Oxygen Defects and Metal–Insulator Transition in Epitaxial Vanadium Dioxides

0.1 eV. The low-energy features of the optical d-d excitation (