Study of the electronic phase transition with low dimensionality in SrVO3 thin films

Abstract

Transport and structural properties of ultrathin films of SrVO 3 (SVO) on SrTiO 3 (001) substrates have been investigated and correlations between Metal-Insulator Transition (MIT) and strain relaxation have been studied.Below a critical thickness, when the film is subjected to tensile strain, the resistivity of the films is increasing with decreasing film thickness. Transport properties evolve from metallic to strongly localized state in several monolayer thick films, showing the bandwidth W control of the Mott-Hubbard transition with the film thickness. Furthermore, a dimensional crossover from 3 Dimensions to 2 Dimensions has been studied by transport measurements. Using Quantum Corrections to the Conductivity (QCC), it is demonstrated that MIT is due to renormalized electron-electron interaction in this material. Finally, for films with the thickness below 6 nm, the confinement provides new effect in magnetotransport with apparition of weak antilocalization in ultrathin films.

Tuning the metal-insulator transition in epitaxial SrVO3 films by uniaxial strain

“…is the 3D weak localization (WL) contribution (P = 2 or 3 is the electronelectron interactions or electron-phone scattering, respectively) [33], while a 2 T Figure 2(b)), which is consistent with previous observations in SVO films [10]. Although QCC successfully describes the insulating region below T MIT, it is not clear whether WL or REEI is the main contribution to the resistivity upturn (or QCC) [33].…”

“…a) shows the XRD scans of the (002) reflection for SVO films without and with irradiation. The pristine SVO film is epitaxial to the STO substrate (a sub = 3.905 Å) and undergoes tensile strain from the substrate, which is in agreement with previous reports[9,10]. With the fluence of He ions increases, the position of the SVO (002) peak exhibits a systematic shift towards the low angle direction, indicating an expansion in the out-of-plane lattice parameter c. The c-axis values can be estimated from the XRD diffraction peaks and are summarized inFigure 1(b).…”

“…This phenomenon is attempted to be interpreted by quantum corrections of the conductivity (QCC) [32]. In this three-dimensional system (3D), the temperature (T) dependence of the resistivity (ρ) can be described by [10,32]:…”

“…Although SVO bulk and films have been extensively studied in the past, exhibiting a robust metallic character and an enhanced Pauli paramagnetic behavior, theoretical studies have predicted that a MIT in SVO thin films can appear as the SVO thickness is reduced to a few unit cells [6,7]. Fortunately, experimental results in ultrathin films seem to verify this prediction: a dimensional-crossover-induced MIT was observed in single SVO ultrathin films [8][9][10][11]. Similar results have also been obtained in other materials, including LaNiO 3 , La 2/3 Ca 1/3 MnO 3 and CaVO 3 [12][13][14].…”

Surface Characterizations and Selective Etching of Sr‐Rich Segregation on Top of SrVO3 Thin‐Films Grown by Pulsed Laser Deposition

“…In these strongly correlated electron materials, the physical properties are driven through the strong interplay between charges, spin, orbital and lattice degree of freedom. Among them, metallic bulk SrVO 3 (SVO) is a normal Fermi liquid,, as it undergoes a Metal to Insulator Mott transition with thickness reduction of few unit cells,, which is still under debates and motivates many SVO‐based heterostructure's studies ,. SVO appears also as a promising candidate in functional oxide electronics and was shown to be useful for metallic electrode applications in oxide heterostructures,, for anodes in solid oxide fuel cells,, and particularly as a transparent conducting oxide (TCO) electrode ,.…”