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

Abstract

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 SrVO 3 (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 new insights into the understanding of MIT in correlated oxides and perspectives for the design of unexpected functional devices based on strongly correlated electrons.

Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO3

“…[ 45 − 47 ] This scenario has been proposed to account for the observation of a metal–insulator transition in ultrathin SVO films [ 8 , 10 , 48 ] and in irradiated SVO films. [ 49 ] However, as we argue in the following, the mass enhancement can also be contributed by e–ph coupling, as the polaronic fits suggest.…”

Electrical transport properties and Kondo effect in La1−xPrxNiO3−δ thin films

“…To further explore the effect of Pr concentration x on electrical transport behaviors, we first analyzed the metallic part of the resistivity. Nickelate is often considered to be a non-Fermi liquid (NFL) 26 – 28 , whose resistivity temperature dependence ( T ) is as follows, with an exponent n < 2 10 , 29 , 30 , where is the residual resistivity and is a coefficient that measures the strength of electron–electron scattering. For a Landau Fermi liquid (LFL), on the other hand, the exponent n equals 2.…”

“…Equation ( 1 ), however, only describes experimental data for a limited range of temperatures 31 . is fully described when the resistivity saturation is taken into account 10 , 29 , 30 , 32 , 33 , and is given by …”

“…Equation (1), however, only describes experimental data for a limited range of temperatures 31 . ρ(T) is fully described when the resistivity saturation ρ SAT is taken into account 10,29,30,32,33 , and ρ(T) is given by Equation 3is called the parallel resistor model and this phenomenological model has been applied to a wide range of materials including elemental metals, heavy fermion compounds, and alloys 34,35 . Here ρ SAT is interpreted as the resistivity at high temperatures where the Ioffe-Regel limit is reached 36 .…”

Coupling of electronic and structural degrees of freedom in vanadate superlattices

“…Therefore, in TMO heterostructures, disentangling the different contributions that lead to a specific orbital occupation is not trivial, for e.g. the influence of bond angles and bond lengths on hopping amplitudes is exactly opposite to one another for a given change in lattice parameter [14]. Moreover, octahedral connectivity and symmetry mismatch at the interfaces have an enormous impact on the crystal structure and therefore must also be considered to accurately predict the electronic structure [15].…”