276 research outputs found
Evidence for lattice-polarization-enhanced field effects at the SrTiO<sub>3</sub>-based heterointerface
Electrostatic gating provides a powerful approach to tune the conductivity of the two-dimensional electron liquid between two insulating oxides. For the LaAlO(3)/SrTiO(3) (LAO/STO) interface, such gating effect could be further enhanced by a strong lattice polarization of STO caused by simultaneous application of gate field and illumination light. Herein, by monitoring the discharging process upon removing the gate field, we give firm evidence for the occurrence of this lattice polarization at the amorphous-LaAlO(3)/SrTiO(3) interface. Moreover, we find that the lattice polarization is accompanied with a large expansion of the out-of-plane lattice of STO. Photo excitation affects the polarization process by accelerating the field-induced lattice expansion. The present work demonstrates the great potential of combined stimuli in exploring emergent phenomenon at complex oxide interfaces
Diluted Oxide Interfaces with Tunable Ground States
The metallic interface between two oxide insulators, such as LaAlO3/SrTiO3
(LAO/STO), provides new opportunities for electronics and spintronics. However,
due to the presence of multiple orbital populations, tailoring the interfacial
properties such as the ground state and metal-insulator transitions remains
challenging. Here, we report an unforeseen tunability of the phase diagram of
LAO/STO by alloying LAO with a ferromagnetic LaMnO3 insulator without forming
lattice disorder and at the same time without changing the polarity of the
system. By increasing the Mn-doping level, x, of LaAl1-xMnxO3/STO, the
interface undergoes a Lifshitz transition at x = 0.225 across a critical
carrier density of nc= 2.8E13 cm-2, where a peak TSC =255 mK of superconducting
transition temperature is observed. Moreover, the LaAl1-xMnxO3 turns
ferromagnetic at x >=0.25. Remarkably, at x = 0.3, where the metallic interface
is populated by only dxy electrons and just before it becomes insulating, we
achieve reproducibly a same device with both signatures of superconductivity
and clear anomalous Hall effect. This provides a unique and effective way to
tailor oxide interfaces for designing on-demand electronic and spintronic
devices.Comment: 18 pages and 6 figure
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