물리학과 강연 (10:30 AM) 자연과학동 공동강의실 1501호

Title : Complex Oxide Heterostructures by Design: How did we get here and where are we going?
Oxide materials are the most abundant compound in the earth’s crust and possess a wide range of electrical, optical, and magnetic properties. For instance, insulators, high quality metals, dielectrics, ferroelectrics, piezoelectrics, semiconductors, ferromagnetics, transparent conductors, ionic conductors, multiferroics superconductors, and nonlinear optical materials have all been produced using oxide materials.  Oxide materials have enormous potential as the fundamental building block of new generations of electronic, magnetic, optical and electromechanical devices. We create these materials by artificially layering various atoms including oxygen at the single atom level, as well as stacking of epitaxial membranes. Our goal is to create new materials and heterostructures with novel properties likely to advance basic science and future applications. I will present advances in epitaxial oxide systems in general, and highlight several examples of how our research has played a role in understanding fundamental solid state phenomena at the atomic scale and in the discovery of new materials.  Atomic layer control of novel oxide heterointerfaces and assembled free standing membranes may provide some of the answers that we need to continue the electronics revolution, particularly for frontier nanoscale devices. I will discuss the challenges and opportunities in this exciting field.

신소재공학과 강연 (15:30 PM) 응용과학동 영상강의실 1502호

Title : Synthesis of Electronic-Grade Quantum Complex Oxide Heterostructures 
Complex oxide heterostructures offer enormous potential as building blocks for novel quantum and electronic devices. However, point defects - such as vacancies and antisite disorders - remain the primary bottleneck limiting electronic mobility and quantum behavior. Traditional synthesis routes, including flux-controlled molecular beam epitaxy (MBE) and single-target pulsed laser deposition (PLD), suffer from extremely narrow growth windows, making stoichiometric control and point-defect reduction exceptionally difficult. To address this challenge, we developed absorption-controlled chemical pulsed laser deposition (CPLD) for SrTiO3 (STO) and a hybrid PLD route for systems containing highly volatile elements, such as potassium in KTaO3 (KTO). For STO, CPLD drastically reduced point defect concentrations, leading to a significant increase in 2DEG electron mobility at the LaAlO3/SrTiO3 interface and revealing clear Shubnikov–de Haas quantum oscillations. For KTO, hybrid PLD successfully counteracted potassium volatility by combining Ta2O5 laser ablation with controlled K2O thermal evaporation. Heteroepitaxial KTO (111) thin films grown via this method exhibited robust interfacial superconductivity with transition temperatures higher than bulk single crystals. These electronic-grade oxide growth platforms provide a powerful foundation for exploring emerging interface physics, strong spin-orbit coupling, and future quantum technologies. I will discuss the current challenges and future opportunities in electronic-grade quantum complex heterostructures and assembled stacked membranes.