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Two-dimensional electron gases (2DEGs) formed at the interface of insulating complex oxides promise the development of all-oxide electronic devices. These 2DEGs involve many-body interactions that give rise to a variety of physical phenomena such as superconductivity, magnetism, tunable metal–insulator transitions and phase separation. Increasing the mobility of the 2DEG, however, remains a major challenge. Here, we show that the electron mobility is enhanced by more than two orders of magnitude by inserting a single-unit-cell insulating layer of polar La 1− x Sr x MnO 3 ( x = 0, 1/8, and 1/3) at the interface between disordered LaAlO 3 and crystalline SrTiO 3 produced at room temperature. Resonant X-ray spectroscopy and transmission electron microscopy show that the manganite layer undergoes unambiguous electronic reconstruction, leading to modulation doping of such atomically engineered complex oxide heterointerfaces. At low temperatures, the modulation-doped 2DEG exhibits Shubnikov–de Haas oscillations and fingerprints of the quantum Hall effect, demonstrating unprecedented high mobility and low electron density. The insertion of La 1− x Sr x MnO 3 in the interface between LaAlO 3 and SrTiO 3 enhances the electron mobility due to charge-transfer-induced modulation doping. Shubnikov–de Haas oscillations and fingerprints of the quantum Hall effect are observed.

The discovery of two-dimensional electron gases at the heterointerface between two insulating perovskite-type oxides, such as LaAlO 3 and SrTiO 3 , provides opportunities for a new generation of all-oxide electronic devices. Key challenges remain for achieving interfacial electron mobilities much beyond the current value of approximately 1,000 cm 2  V -1  s -1 (at low temperatures). Here we create a new type of two-dimensional electron gas at the heterointerface between SrTiO 3 and a spinel γ-Al 2 O 3 epitaxial film with compatible oxygen ions sublattices. Electron mobilities more than one order of magnitude higher than those of hitherto-investigated perovskite-type interfaces are obtained. The spinel/perovskite two-dimensional electron gas, where the two-dimensional conduction character is revealed by quantum magnetoresistance oscillations, is found to result from interface-stabilized oxygen vacancies confined within a layer of 0.9 nm in proximity to the interface. Our findings pave the way for studies of mesoscopic physics with complex oxides and design of high-mobility all-oxide electronic devices. Highly mobile electrons at the interface of two perovskite oxides are of considerable interest for electronic applications. In this work, the discovery of such an electron gas at the interface of a spinel and a perovskite oxide represents a new approach to look for oxide systems with enhanced properties.

Interfaces between complex oxides host a plethora of functional properties including enhanced ionic conductivity, gate-tunable superconductivity and exotic magnetic states. The enhanced electronic, ionic and magnetic properties along the oxide interfaces are generally exploited in functional devices by spatial confinement of ions and electrons. Different patterning methods have been used to spatially control the conductivity at the interface, but a key limitation is the multiple steps needed to fabricate functional devices. In this investigation, inkjet printing of thermally stable oxides is introduced as an alternative pathway for spatially controlling the interface conductivity. We inkjet print yttrium-stabilized zirconia and TiO2 with various shapes and use these as physical masks to confine the electronic conductivity in SrTiO3-based heterostructures. By performing in-situ transport measurements of the electrical conductivity as LaAlO3 and γ-Al2O3 are deposited on SrTiO3, we witness the birth of the interface conductivity and find a consistent transient behavior as conductivity emerges in patterned and non-patterned heterostructures. We find that conductivity appears after the first laser pulse in the pulsed laser deposition corresponding to the film covering only a few percent of the substrate. We attribute the emergence of conductivity to oxygen vacancies formed by a combination of plasma bombardment and oxygen transfer across the interface during growth. In this vein, inkjet patterned hard masks protects the SrTiO3 substrate, effectively confining the conductivity. The study paves a scalable way for realizing energy devices with spatially controlled electronic and ionic interface conductivity.

Thoracentesis is a common clinical procedure, but the optimal training method remains unclear. To investigate whether a novel teaching program combining e-learning and simulation-based self-directed, spaced learning (intervention) is non-inferior to a traditional instructor-led massed training approach (control). In this multicenter randomized, non-inferiority study, emergency physicians unable to perform thoracentesis were randomized to either the intervention group (e-learning and three self-directed simulation sessions over two weeks) or a control group (single three-hour instructor-led simulation course). Skill acquisition and retention were evaluated at two weeks and three months by blinded assessors. The primary outcome was passing rate at two weeks post training, with a non-inferiority margin of 10 %. Secondary outcome was passing rate at three months. A total of 63 participants (intervention group: 29, control group: 34) were included. The majority were female (72 % in the intervention group vs. 50 % in the control group). At two weeks, passing rates were 66 % (19/29) in intervention group and 65 % (18/26) control, with a risk difference of 0.8 %, CI-95 %: −30 %;30 %, p = 0.96. At three months, skill retention was significantly higher in the intervention group (92 %) compared to the control group (73 %), with a risk difference of 19 % CI-95 %: 10 %;30 %, p < 0.001. A novel training approach with self-directed spaced learning for thoracentesis resulted in comparable skill acquisition when comparing to traditional instructor-led massed training although the study was underpowered to demonstrate non-inferiority. Self-directed spaced learning was associated with superior for skill retention compared to instructor-led massed training after three months.

Interfaces between complex oxides host a plethora of functional properties including enhanced ionic conductivity, gate-tunable superconductivity and exotic magnetic states. The enhanced electronic, ionic and magnetic properties along the oxide interfaces are generally exploited in functional devices by spatial confinement of ions and electrons. Different patterning methods have been used to spatially control the conductivity at the interface, but a key limitation is the multiple steps needed to fabricate functional devices. In this investigation, inkjet printing of thermally stable oxides is introduced as an alternative pathway for spatially controlling the interface conductivity. We inkjet print yttrium-stabilized zirconia and TiO 2 with various shapes and use these as physical masks to confine the electronic conductivity in SrTiO 3 -based heterostructures. By performing in-situ transport measurements of the electrical conductivity as LaAlO 3 and γ -Al 2 O 3 are deposited on SrTiO 3 , we witness the birth of the interface conductivity and find a consistent transient behavior as conductivity emerges in patterned and non-patterned heterostructures. We find that conductivity appears after the first laser pulse in the pulsed laser deposition corresponding to the film covering only a few percent of the substrate. We attribute the emergence of conductivity to oxygen vacancies formed by a combination of plasma bombardment and oxygen transfer across the interface during growth. In this vein, inkjet patterned hard masks protects the SrTiO 3 substrate, effectively confining the conductivity. The study paves a scalable way for realizing energy devices with spatially controlled electronic and ionic interface conductivity.

The discovery of two-dimensional electron gases at the heterointerface between two insulating perovskite-type oxides, such as LaAlO(3) and SrTiO(3), provides opportunities for a new generation of all-oxide electronic devices. Key challenges remain for achieving interfacial electron mobilities much beyond the current value of approximately 1,000 cm(2) V(-1) s(-1) (at low temperatures). Here we create a new type of two-dimensional electron gas at the heterointerface between SrTiO(3) and a spinel γ-Al(2)O(3) epitaxial film with compatible oxygen ions sublattices. Electron mobilities more than one order of magnitude higher than those of hitherto-investigated perovskite-type interfaces are obtained. The spinel/perovskite two-dimensional electron gas, where the two-dimensional conduction character is revealed by quantum magnetoresistance oscillations, is found to result from interface-stabilized oxygen vacancies confined within a layer of 0.9 nm in proximity to the interface. Our findings pave the way for studies of mesoscopic physics with complex oxides and design of high-mobility all-oxide electronic devices.

Two-dimensional (2D) Rashba systems have been intensively studied in the last decade due to their unconventional physics, tunability capabilities, and potential for spin-charge interconversion when compared to conventional heavy metals. With the advent of a new generation of spin-based logic and memory devices, the search for Rashba systems with more robust and larger conversion efficiencies is expanding. Conventionally, demanding techniques such as angle- and spin-resolved photoemission spectroscopy are required to determine the Rashba parameter \\(\\alpha_{R}\\) that characterizes these systems. Here, we introduce a simple method that allows a quantitative extraction of \\(\\alpha_{R}\\), through the analysis of the bilinear response of angle-dependent magnetotransport experiments. This method is based on the modulation of the Rashba-split bands under a rotating in-plane magnetic field. We show that our method is able to correctly yield the value of \\(\\alpha_{R}\\) for a wide range of Fermi energies in the 2D electron gas at the LaAlO\\(_{3}\\)/SrTiO\\(_{3}\\) interface. By applying a gate voltage, we observe a maximum \\(\\alpha_{R}\\) in the region of the band structure where interband effects maximize the Rashba effect, consistently with theoretical predictions.

Metallic LaAlO\\(_3\\)/SrTiO\\(_3\\) (LAO/STO) interfaces attract enormous attention, but the relationship between the electron mobility and the sheet electron density, \\(n_s\\), is poorly understood. Here we derive a simple expression for the three-dimensional electron density near the interface, \\(n_{3D}\\), as a function of \\(n_s\\) and find that the mobility for LAO/STO-based interfaces depends on \\(n_{3D}\\) in the same way as it does for bulk doped STO. It is known that undoped bulk STO is strongly compensated with \\(N \\simeq 5 \\times 10^{18}~\\rm{cm^{-3}}\\) background donors and acceptors. In intentionally doped bulk STO with a concentration of electrons \\(n_{3D} < N\\) background impurities determine the electron scattering. Thus, when \\(n_{3D} < N\\) it is natural to see in LAO/STO the same mobility as in the bulk. On the other hand, in the bulk samples with \\(n_{3D} > N\\) the mobility collapses because scattering happens on \\(n_{3D}\\) intentionally introduced donors. For LAO/STO the polar catastrophe which provides electrons is not supposed to provide equal number of random donors and thus the mobility should be larger. The fact that the mobility is still the same implies that for the LAO/STO the polar catastrophe model should be revisited.

A new species of Eleocharis, E. cordillerana (Cyperaceae) is described and illustrated. This species is endemic to Southern Chile, and its relationships at species level remain unclear. Se describe e ilustra Eleocharis cordillerana (Cyperaceae), una especie nueva, endémica del sur de Chile, cuyas relaciones a nivel específico son poco claras.

The discovery of two-dimensional electron gases (2DEGs) at the heterointerface between two insulating perovskite-type oxides, such as LaAlO3 and SrTiO3, provides opportunities for a new generation of all-oxide electronic and photonic devices. However, significant improvement of the interfacial electron mobility beyond the current value of approximately 1,000 cm2V-1s-1 (at low temperatures), remains a key challenge for fundamental as well as applied research of complex oxides. Here, we present a new type of 2DEG created at the heterointerface between SrTiO3 and a spinel {\\gamma}-Al2O3 epitaxial film with excellent quality and compatible oxygen ions sublattices. This spinel/perovskite oxide heterointerface exhibits electron mobilities more than one order of magnitude higher than those of perovskite/perovskite oxide interfaces, and demonstrates unambiguous two-dimensional conduction character as revealed by the observation of quantum magnetoresistance oscillations. Furthermore, we find that the spinel/perovskite 2DEG results from interface-stabilized oxygen vacancies and is confined within a layer of 0.9 nm in proximity to the heterointerface. Our findings pave the way for studies of mesoscopic physics with complex oxides and design of high-mobility all-oxide electronic devices.