Lu Li - US grants

Non-technical abstract:
Quantum materials are an emergent field integrating many science disciplines to develop next generation electronic and energy technology. A well-known example of quantum materials is the high temperature superconductor, which brings promise of electricity transfer without energy loss. The acquisition of the cryogen-free Physical Properties Measurement System (PPMS) enables researchers at the University of Michigan to measure the properties of next-generation materials. The fundamental understanding gained from the study of quantum materials lays the foundation for future electronics, including high-density hard drives, quantum computers, and semiconductor panels that generate electricity using solar energy or waste heat from your car engine. The PPMS provides excellent avenues for training graduate and undergraduate students. The students perform research using state-of-the-art equipment and receive education and training in an interdisciplinary environment. PPMS allows undergraduate and high school students, doing research with the investigators, and those taking upper level physics laboratory courses, to easily and safely perform experiments at cryogenic temperatures. The investigators leverage existing REU and bridge-to-PhD programs to bring in students from underrepresented groups to participate in projects on quantum electronic materials, which enhance the diversity of the future US STEM workforce.

Technical Abstract:
The acquisition of a cryogen-free Physical Properties Measurement System (PPMS) with a 14 Tesla magnet enables studies of novel quantum materials at the University of Michigan in order to answer the following important problems. (1). What fundamentally new physics and novel functionalities can be achieved in 2D electronic systems by strong electronic correlations, interface engineering, and edge valley polarization? (2). Why are the most well known 3D Dirac electronic systems good thermoelectric materials? (3). What are the key parameters determining the optoelectronic properties of dilute semiconductor alloys? (4). How are spins coupled to the electronic degrees of freedom in conventional and novel semiconductors? Aiming to answer these fundamental questions, the scope of research includes: (1) Emergent novel two-dimensional electronic systems, (2) Enhanced Thermoelectric materials in 3D Dirac electronic systems, (3) Physical properties of Semiconductor Alloys, and (4) Manipulating spin and magnetic properties in semiconductors. The methods and approaches of the research explore a broad range of physical properties including resistivity, Hall effect, magnetization, heat capacity, AC susceptibility, thermal conductivity, and thermopower. The studies enable understanding of physical mechanisms, and lay the foundation for important and novel applications of quantum materials.