A5100376252- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Magnetic and transport properties of perovskites and related materials
- Ferroelectric and Piezoelectric Materials
- Ferroelectric and Negative Capacitance Devices
- Graphene research and applications
- Particle physics theoretical and experimental studies
- Advanced Condensed Matter Physics
- Quantum and electron transport phenomena
- Advanced Materials Characterization Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Chromodynamics and Particle Interactions
- Advanced Memory and Neural Computing
- Advanced X-ray and CT Imaging
- Analytical Chemistry and Sensors
- Acoustic Wave Resonator Technologies
- Multiferroics and related materials
- High-Energy Particle Collisions Research
- Molecular Junctions and Nanostructures
- Carbon Nanotubes in Composites
- Physics of Superconductivity and Magnetism
- Diamond and Carbon-based Materials Research
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor Lasers and Optical Devices
- Catalytic Processes in Materials Science
University of Wisconsin–Madison
2016-2024
Hongik University
2024
Pusan National University
2024
The Ohio State University
1999-2022
Yonsei University
2022
Cornell University
1997-2020
University of Cambridge
2020
University of Hong Kong
2020
Madison Group (United States)
2019
Keimyung University
2016
This perspective considers the enormous promise of epitaxial functional transition metal oxide thin films for future applications in low power electronic and energy since they offer wide-ranging highly tunable functionalities multifunctionalities, unrivaled among other classes materials. It also great challenges that must be overcome to meet what is needed application domain. These arise from presence intrinsic defects strain effects, which lead extrinsic defects. Current conventional film...
SrTiO3-based heterointerfaces support quasi-two-dimensional (2D) electron systems that are analogous to III–V semiconductor heterostructures, but also possess superconducting, magnetic, spintronic, ferroelectric, and ferroelastic degrees of freedom. Despite these rich properties, the relatively low mobilities 2D complex-oxide interfaces appear preclude ballistic transport in 1D. Here we show LaAlO3/SrTiO3 interface can quantized electrons (nonsuperconducting) pairs within quasi-1D structures...
An unusual conductance sequence Effects of correlations between electrons are enhanced in systems reduced dimensions. The two-dimensional interface two oxide materials, lanthanum aluminate (LaAlO 3 ) and strontium titanate (SrTiO ), exhibits magnetism superconductivity. In even lower-dimensional fabricated similar heterostructures, can pair without going superconducting. Briggeman et al. have now observed another exotic effect LaAlO /SrTiO waveguides: At certain magnetic fields, the these...
We examine superconductivity in ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ channels with widths that transition from the 1D to 2D regime. The superconducting critical current is independent of channel width and increases approximately linearly number parallel channels. Signatures electron pairing outside regime are also found be width. Collectively, these results indicate exists at boundary absent within interior region intrinsic nature interface imposes strong physical constraints on...
Strontium titanate (SrTiO3) is the "silicon" in emerging field of oxide electronics. While bulk properties this material have been studied for decades, new unexpected phenomena recently discovered at nanoscale, when SrTiO3 forms an ultrathin film or atomically sharp interface with other materials. One striking discoveries room-temperature ferroelectricity strain-free films driven by TiSr antisite defects, which generate a local dipole moment polarizing surrounding nanoregion. Here, we...
We report an oxygen surface adsorbates induced metal–insulator transition at the LaAlO3/SrTiO3 interfaces. The observed effects were attributed to terminations of Al sites and resultant electron-accepting states. By controlling local adsorptions, we successfully demonstrated nondestructive patterning interface two-dimensional electron gas (2DEG). obtained 2DEG structures are stable in air also robust against general solvent treatments. This study provides new insights into mechanism complex...
Oxide interface orientation tunes ferroelectric distortion and antiferrodistortive rotation into competition or cooperation.
KTaO 3 heterostructures have recently attracted attention as model systems to study the interplay of quantum paraelectricity, spin-orbit coupling, and superconductivity. However, high low vapor pressures potassium tantalum present processing challenges creating heterostructure interfaces clean enough reveal intrinsic properties. Here, we report superconducting based on high-quality epitaxial (111) thin films using an adsorption-controlled hybrid PLD overcome pressure mismatch. Electrical...
Freestanding membranes of electronically reconfigurable complex oxide heterostructure are demonstrated.
Fabrication of epitaxial FeSexTe1-x thin films using pulsed laser deposition (PLD) enables improving their superconducting transition temperature (T c) by more than ~40% bulk T c. Intriguingly, c enhancement in has been observed on various substrates and with different Se content, x. To date, mechanisms for have reported, but they remain controversial universally explaining the improvement films. In this report, we demonstrate that controversies over mechanism are due to abnormal changes...
Real-time probes profile changes in vacancy distributions within substrate-supported oxide films induced by deposition processes.
We report the low-frequency noise behaviors in quasi-two-dimensional (quasi-2D) electron systems based on complex oxide heterostructures. First, surface 2D gas (2DEG) SrTiO3 (STO) exhibits 1/fα-type current power spectral density (PSD) with α∼1.39. The non-unity exponent α indicates discrepancy between depth distributions of electrons and oxygen vacancies STO substrate. Second, amorphous LaAlO3/KTaO3 (LAO/KTO) interface, another quasi-2D system, shows Lorentzian components PSD at a...
The widely reported magnetoresistance oscillations in LaAlO_{3}/SrTiO_{3} heterostructures have invariably been attributed to the Shubnikov-de Haas (SdH) effect, despite a pronounced inconsistency with low-field Hall resistance measurements. Here we report SdH-like quasi-1D electron waveguides created at interface by conductive atomic force microscopy lithography. These can be directly magnetic depopulation of magnetoelectric subbands. Our results suggest that SdH 2D SrTiO_{3}-based systems...
Unveiling both the presence and nature of point defects is one biggest challenges in condensed matter physics materials science. Particularly complex oxides, even a minute amount unavoidable could generate novel physical phenomena functions, such as visible light emission ferroelectricity, yet it remains elusive to clearly identify defects. Here, taking $\mathrm{SrTi}{\mathrm{O}}_{3}$ model system, we show that iterative feedback among atomic-layer- stoichiometry-controlled thin-film...
$\beta$ decay of $^{26}$P was used to populate the astrophysically important $E_x=$5929.4(8) keV $J^{\pi}=3{^+}$ state $^{26}$Si. Both $\beta$-delayed proton at 418(8) and gamma ray 1742(2) emitted from this were measured simultaneously for first time with corresponding absolute intensities 11.1(12)\% 0.59(44)\%, respectively. Besides, shell model calculations weakly bound effects performed investigate properties other resonant states a spin-parity $4^+$ rather than $0^+$ favored...
We have grown and characterized (110)-oriented YBa2Cu3O7−x (YBCO)/PrBa2(Cu0.8Ga0.2)3O7−x (PBCGO) bilayer YBCO/PBCGO/YBCO trilayer heterostructures, which were deposited by pulsed laser deposition technique for the nanofabrication of YBCO-based superconductor (S)/insulator (I)/superconductor (S) tunneling vertical geometry Josephson junction other electronic devices. The structural properties these investigated through various x-ray diffraction techniques (profile, reflectivity, pole figure,...
In correlated materials including transition metal oxides, electronic properties and functionalities are modulated enriched by couplings between the electron lattice degrees of freedom. These controlled external parameters such as chemical doping, pressure, magnetic electric fields, light irradiation. However, electron-lattice coupling relies on orbital characters, i.e., symmetry occupancy, t2g eg orbitals, so that a large is limited to system, whereas system exhibits an inherently weak...
The quest to understand, design, and synthesize new forms of quantum matter guides much contemporary research in condensed physics. One-dimensional (1D) electronic systems form the basis for some most interesting exotic phases matter. variety experimentally-accessible ballistic 1D is highly restricted, furthermore these typically have few tuning parameters other than electric magnetic fields. However, electron waveguides formed from two-dimensional (2D) LaAlO$_3$/SrTiO$_3$ heterointerfaces...
Here, we demonstrate the nanoscale manipulations of two types charge transfer to LaAlO3/SrTiO3 interfaces: one from surface adsorbates and another oxygen vacancies inside LaAlO3 films. This method can be used produce multiple insulating metallic interface states with distinct carrier properties that are highly stable in air. By reconfiguring patterning comparing structures formed different doping sources, effects extrinsic intrinsic material characters on transport distinguished. In...
Abstract The ability to combine continuously tunable narrow-band terahertz (THz) generation that can access both the far-infrared and mid-infrared regimes with nanometer-scale spatial resolution is highly promising for identifying underlying light-matter interactions realizing selective control of rotational or vibrational resonances in nanoparticles molecules. Here, we report difference frequency over 100 THz bandwidth via femtosecond optical pulse shaping. emission generated at nanoscale...
SrRuO3 (SRO) has emerged as a promising quantum material due to its exotic electron correlations and topological properties. In epitaxial SRO films, scattering against lattice phonons or defects been considered only predominant mechanism accounting for electronic Although the charge trapping by polar can also strongly influence behavior, it often neglected. Herein, we report strong interfacial in ultrathin films on SrTiO3 (STO) substrates probed noise spectroscopy. We find that oxygen...