Insulator-to-metal transition and correlated metallic state of V2O3investigated by optical spectroscopy

Abstract

The optical properties of V 2 O 3 thin films are investigated across the insulator-to-metal transition and in the metallic state. The spectral weight transfer observed across the transition, over an energy scale of 5 eV, is consistent with the Mott-Hubbard model for correlated electron systems. In the metallic phase, a strong Drude peak is observed, which exhibits a pronounced temperature dependence related to the transfer of states from the Hubbard bands to the quasiparticle peaks as the temperature is reduced. The analysis of the far-infrared spectra reveals signatures of strong electronic correlations in V 2 O 3. Finally, a comparison to VO 2 data is presented.

Facile synthesis and phase transition of V2O3 nanobelts

“…[15,17] To further explore the phase transition of the V2O3 nanobelts, we also utilized variable-temperature Raman spectroscopy (VT-Raman) to measure the Tc of individual V2O3 nanobelts. Compared to other methods such as variable-temperature XRD, [9] optical [18] and electrical measurements, [14] VT-Raman is capable of detecting individual material with high spatial resolution and does not require complicated lithographic fabrications. So this method was widely used to trace the phase transition of low dimensional materials [19] , including V2O3 [20,21] We first measured the Raman spectra of V2O3 nanobelts sitting on 300 nm SiO2/Si substrates in vacuum at room temperature by mapping a few V2O3 nanobelts (Fig.…”

Dynamic conductivity scaling in photoexcitedV2O3thin films

“…At a minimum, neglecting mesoscale effects can lead to a misinterpretation of the dynamics. More importantly, as shown in this work, mesoscale dynamics are of intrinsic interest from fundamental and applied perspectives.V 2 O 3 is a paramagnetic metal with rhombohedral crystal symmetry [30][31][32][33][34][35] which undergoes a first order phase transition to an antiferromagnetic insulating state at T IM T = 175K, accompanied by a change to a monoclinic crystal structure [36]. In this work, we present mesoscopic conductivity dynamics of V 2 O 3 across the insulator-to-metal transition following an optically initiated picosecond thermal quench into the metallic state.…”

“…Our analysis further indicates that the metallic phase grows ballistically, at the sound velocity. 95nm thick V 2 O 3 films were grown in an ultrahigh purity Ar environment by rf magnetron sputtering of a V 2 O 3 target onto an r-plane (1012) sapphire substrate [34]. X-ray diffraction characterization indicates near single crystal growth following the substrate orientation.…”

On the energy scale involved in the metal to insulator transition of quadruple perovskite EuCu3Fe4O12: infrared spectroscopy and ab-initio calculations

“…It clearly deviates from usual Drude model since it exhibits a broad bump at 200 cm −1 . This could be due to either localization by disorder293031, electronic correlations3233 or strong electron-lattice coupling (polarons)293435. With decreasing temperature, the optical conductivity dramatically drops three order of magnitude at low frequency, and exhibits an insulating behavior, with an optical gap energy Δ ≈ 125 meV and a broad mid infrared band.…”