活動資訊-TOSIA 台灣光電暨化合物半導體產業協會

時代基金會將於 8 月 26 日(一)，邀請 MIT 材料科學暨工程學系的 Prof. Ju Li 訪台，針對如何將奈米材料超強度性應用於彈性應變工程，進行專題演講。未來奈米材料於半導體元件、光伏電池、LED 、超導、感測器領域皆扮演關鍵性的元素。

Prof. Ju Li 曾於 2014 及 2018 年兩度獲 Thomson Reuters/ Clarivate 選入，材料科學領域的 Highly Cited Researchers List。 

演講主題：Ultra-strength Materials and Elastic Strain Engineering超強材料與彈性應變工程

演講大綱：
Recent experiments on nanostructured materials have revealed a host of "ultra-strength" phenomena, defined by stresses in a material component generally rising up to a significant fraction (>1/10) of its ideal strength, ­ the highest achievable stress of a defect-free crystal at zero temperature. While conventional materials deform or fracture at sample-wide stresses far below the ideal strength, rapid development of nanotechnology has brought about a need to understand ultra-strength phenomena, as nanoscale materials apparently have a larger dynamic range of sustainable stress ("strength") than conventional materials. Ultra-strength phenomena not only have to do with the shape stability and deformation kinetics of a component, but also the tuning of its physical and chemical properties by stress. Reaching ultra-strength enables ``elastic strain engineering", where by controlling the elastic strain field one can guide the interactions of material structures with electrons, photons, etc. and control energy, mass and information flows.

The success of Strained Silicon technology today harbingers what Strain Engineering may do for human civilization in the future, with potential breakthroughs in electronics, photonics, ferroics, superconductivity, catalysis, sensing, etc. In this talk I will give examples of exploiting the strain design space of low-dimensional materials.

Homogenous and inhomogeneous elastic strain, bending, interlayer twist and slip lead to tunable, low-energy artificial atoms, artificial superlattices and pseudoheterostructures that can regulate quasiparticle motion. Strain also governs ferroelastic and band topology transitions in these materials. Lastly, we demonstrate production of kilogram-scale nanowires under large tensile elastic strain, that leads to improved superconductivity. By controlling the strain tensor and strain gradient statically or dynamically, one opens up a much larger parameter space - on par with alloying - for optimizing the functional properties of materials, which imparts a new meaning to Feynman’s statement "There's Plenty of Room at the Bottom".