Tunable strain effect and ferroelectric field effect on the electronic transport properties of La0.5Sr0.5CoO3 thin films

Abstract

Tensiled La0.5Sr0.5CoO3 (LSCO) thin films were epitaxially grown on piezoelectric 0.67Pb (Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) single-crystal substrates. Due to the epitaxial nature of the interface, the lattice strain induced by ferroelectric poling or the converse piezoelectric effect in the PMN-PT substrate is effectively transferred to the LSCO film and thus reduces the tensile strain of the film, giving rise to a decrease in the resistivity of the LSCO film. We discuss these strain effects within the framework of the spin state transition of Co3+ ions and modification of the electronic bandwidth that is relevant to the induced strain. By simultaneously measuring the strain and the resistivity, quantitative relationship between the resistivity and the strain was established for the LSCO film. Both theoretical calculation and experimental results demonstrate that the ferroelectric field effect at room temperature in the LSCO/PMN-PT field-effect transistor is minor and could be neglected. Nevertheless, with decreasing temperature, the ferroelectric field effect competes with the strain effect and plays a more and more important role in influencing the electronic transport properties of the LSCO film, which we interpreted as due to the localization of charge carriers at low temperature.

Enhanced conductivity at orthorhombic–rhombohedral phase boundaries in BiFeO3 thin films

“…[11][12][13][14][15][16][17] Mixed-phase regions exhibit the coexistence of both R-and T-like phases with the ability to selectively switch between the two phases by an external electric field and force. [18][19][20][21][22] Interestingly, the strong correlation between T-R interfaces and their enhanced properties, such as the finding of a large electric-field-induced strain 23 and a giant piezoelectric d 33 coefficient, led to extensive studies of bismuth ferrite films under compressive strain by both experimental and theoretical approaches. Moreover, a correlation between the elasticity at the T-R interfaces and electronic conduction was also reported.…”

Charge redistribution in correlated heterostuctures within nonequilibrium real-space dynamical mean-field theory

“…where v α=l/r + v (0) α=l/r and E α=l/r (k) denote the onsite energies and the dispersion relation for the left/right lead, respectively. The sign of the square-root for negative argument in (6) must be chosen such that the Green's function has the correct 1/ω behavior for |ω| → ∞. Since the disconnected leads are separately in equilibrium, we can obtain their Keldysh components from the retarded ones via the fluctuation dissipation theorem 73…”

“…Correlated systems out of equilibrium and especially electronic transport through heterostructures made from different materials, have attracted increasing interest due to the recent impressive experimental progress to fabricate correlated heterostructures [1][2][3][4][5][6] with atomic resolution and, in particular, growing atomically abrupt layers with different electronic structures [1][2][3] .…”

Resonance effects in correlated multilayer heterostructures

“…Recent experimental progress makes it possible to fabricate correlated heterostructures [19][20][21][22][23][24] with atomic resolution and in particular, growing atomically abrupt layers with different electronic structures [20][21][22] . Here, we study a system which is composed of alternating strongly correlated and non-correlated metallic layers, as well as band insulator layers (see Fig.…”