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


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

Wang, C.; Zhang, H.; Deepak, K.; Chen, C.; Fouchet, A.; Duan, J.; Hilliard, D.; Kentsch, U.; Chen, D.; Zeng, M.; Gao, X.; Zeng, Y.-J.; Helm, M.; Prellier, W.; Zhou, S.

Understanding of the metal-insulator transition (MIT) in correlated transition-metal oxides is a fascinating topic in condensed matter physics and a precise control of such transitions plays a key role in developing novel electronic devices. Here we report an effective tuning of the MIT in epitaxial SrVO3 (SVO) films by expanding the out-of-plane lattice constant without changing in-plane lattice parameters, through helium ion irradiation. Upon increase of the ion fluence, we observe a MIT with a crossover from metallic to insulating state in SVO films. A combination of transport and magnetoresistance measurements in SVO at low temperatures reveals that the observed MIT is mainly ascribed to electron-electron interactions rather than disorder-induced localization. Moreover, these results are well supported by the combination of density functional theory and dynamical mean field theory (DFT+DMFT) calculations, further confirming the decrease of the bandwidth and the enhanced electron-electron interactions resulting from the expansion of out-of-plane lattice constant. These findings provide insights into the understanding of MIT in correlated oxides and perspectives for the design of unexpected functional devices based on strongly correlated electrons.

Keywords: Oxide thin film; Strain engineering; Metal-insulator transition; Lattice distortion; Correlated electrons

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