MSE Department Seminar

The phenomena in which a magnetic or electric polarization is induced via an external electric or magnetic field has attracted renewed research interest owing to the possibility of creating novel electronic and optoelectronic devices. In this direction, multifunctional materials such as multiferroics, with their enhanced coupling between electronic, vibrational, and spin degrees of freedom, are ushering in a new era of revolutionary advances in optoelectronics, spintronics, and quantum sensing.

A crucial yet unavailable component in high-performance photonic integrated circuits (ICs) and other chip-scale photonic systems is an on-chip light source that is efficient, functional, IC-compatible, and electronically addressable. In this talk, I will cover several types of on-chip sources, including perovskite microlasers and luminescent hyperbolic metamaterials, topologically protected microlasers on the III-V platform, as well as spintronic THz emitters on the III-N platform.

Quantum technologies have progressed greatly over the past 3 decades, with qubits coherence times approaching millisecond lifetimes. However, it is recognized that to scale quantum computing to the level required for tackling problems of practical importance, many challenges remain. Challenges including predictability & stability of qubit performance, circuit size shrinking, qubit control / read-out, and quantum signal transduction to telecom-optical wavelengths need to be urgently addressed.

We provide an overview of a NASA University Leadership Initiative project entitled “Development of an Ecosystem for Qualification of Additive Manufacturing Processes and Materials in Aviation”. This involved multiple universities and other collaborators working together to build a quantitative connection between AM processing, microstructure and properties in laser powder bed fusion of Ti-6Al-4V. Microstructure focused on defect structure and the key property was fatigue.

Developing electronics beyond Moore's Law requires a revolutionary vision in new materials, novel devices, disruptive technologies, and alternative computer architecture. A memristor (resistance switch) is an emerging device that uses resistance states to represent digital or analog information. Built into large-scale crossbar arrays, they perform efficient analog multiply-accumulate operations with massive parallelism by directly using physical laws.

Since the beginning of the microelectronics era ongoing miniaturization of transistors has been accompanied by the development of ever more intricate interconnects. Presently these range from nanoscale on-chip wiring to 3D TSV for chip stacking along with related structures for advanced packaging and printed circuit board applications. Electrodeposition has been a key process in the void-free fabrication of recessed patterned Cu interconnects by virtue of surfactant-mediated superconformal film growth.

The unique ability of carbon to bond with itself forming extended chains and networks underlies the structural complexity of organic matter. This complexity extends to elemental carbon. Several hundred crystalline carbon phases have been theoretically predicted to date. However, few of these materials have been realized experimentally. Advances in the synthesis of nonbenzenoid and sp1-containing allotropes have been especially limited.

The advancement of quantum photonic technologies relies on the ability to precisely control the degrees of freedom of optically active states. First, motivated by recent evidence showing that nanowrinkles generate strain-localized room-temperature emitters, we demonstrate a method to intentionally induce wrinkles with collections of stressors. We show that long-range wrinkle direction and position are controllable with patterned array design, forming quantum emitters as evidenced by cryogenic anti-bunched emission.

The ever-growing demand for sustainable transportation and renewable energy sources has placed a critical spotlight on lithium batteries, which are key to unlocking a cleaner future. However, current lithium-ion battery technology has reached its theoretical energy density limit and cannot meet these demands. Developing new battery chemistries with high energy density has been challenging due to the intrinsic complexity of batteries. This complexity includes defects in materials, inhomogeneity in manufacturing, and phase transitions and interphase formation under electrochemical dynamics.

Nature provides extraordinary examples of high-performance polymers with properties often surpassing those of man-made plastics. Protein-based materials are particularly interesting because their palette of amino acid “monomers” and their precisely controlled sequence can give rise to complex properties based on the synergy of diverse intermolecular interactions. Silk fibroin, a class of proteins produced by many insects and arachnids, is an archetypal elastomer with an unrivaled combination of strength and toughness.