Judith Gabel

In Situ Control of Separate Electronic Phases on SrTiO3 Surfaces by Oxygen Dosing

Insulating SrTiO3 (STO) can host 2D electron systems (2DESs) on its surfaces, caused by oxygen defects. This study shows that the STO surface exhibits phase separation once the 2DES is formed and relates this inhomogeneity to recently reported magnetic order at STO surfaces and interfaces. The results open pathways to exploit oxygen defects for engineering the electronic and magnetic properties of oxides.

Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy

The spinel/perovskite heterointerface

Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator

\ensuremath{\gamma}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}/{\mathrm{SrTiO}}_{3}

Gate-tunable, normally-on to normally-off memristance transition in patterned LaAlO3/SrTiO3 interfaces

hosts a two-dimensional electron system (2DES) with electron mobilities exceeding those in its all-perovskite counterpart

Surface-interface coupling in an oxide heterostructure: Impact of adsorbates onLaAlO3/SrTiO3

{\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}

Bulk nature of layered perovskite iridates beyond the Mott scenario: An approach from a bulk-sensitive photoemission study

by more than an order of magnitude, despite the abundance of oxygen vacancies which act as electron donors as well as scattering sites. By means of resonant soft x-ray photoemission spectroscopy and ab initio calculations, we reveal the presence of a sharply localized type of oxygen vacancies at the very interface due to the local breaking of the perovskite symmetry. We explain the extraordinarily high mobilities by reduced scattering resulting from the preferential formation of interfacial oxygen vacancies and spatial separation of the resulting 2DES in deeper

Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO3

{\mathrm{SrTiO}}_{3}

Disentangling specific versus generic doping mechanisms in oxide heterointerfaces

layers. Our findings comply with transport studies and pave the way towards defect engineering at interfaces of oxides with different crystal structures.

New type of in-gap states at a spinel/perovskite interface: combined resonant soft x-ray photoemission spectroscopy and first-principles study.

The Mott transistor is a paradigm for a new class of electronic devices-often referred to by the term Mottronics-which are based on charge correlations between the electrons. Since correlation-induced insulating phases of most oxide compounds are usually very robust, new methods have to be developed to push such materials right to the boundary to the metallic phase in order to enable the metal-insulator transition to be switched by electric gating. Here, it is demonstrated that thin films of the prototypical Mott insulator LaTiO3 grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band-filling controlled Mott transition in the electronic phase diagram. The detected insulator to metal transition is characterized by a strong change in resistivity of several orders of magnitude. The use of suitable substrates and capping layers to inhibit oxygen diffusion facilitates full control of the oxygen content and renders the films stable against exposure to ambient conditions. These achievements represent a significant advancement in control and tuning of the electronic properties of LaTiO3+x thin films making it a promising channel material in future Mottronic devices.

パターン化LaAlO3/SrTiO3界面におけるゲート調整可能,通常オンから通常オフへのメモリスタンス転移

We report gate-tunable memristive switching in patterned LaAlO3/SrTiO3 interfaces at cryogenic temperatures. The application of voltages in the order of a few volts to the back gate of the device allows controlling and switching on and off the inherent memory functionality (memristance). For large and small gate voltages, a simple non-linear resistance characteristic is observed, while a pinched hysteresis loop and memristive switching occur in an intermediate voltage range. The memristance is further controlled by the density of oxygen vacancies, which is tuned by annealing the sample at 300 °C in a nitrogen atmosphere. Depending on the annealing time, the memristance at zero gate voltage can be switched on and off, leading to normally-on and normally-off memristors. The presented device offers reversible and irreversible control of memristive characteristics by gate voltages and annealing, respectively, which may allow compensating fabrication variabilities of memristors that complicate the realization ...