Strain and Defect Induced Phenomena in van der Waals Materials: WSe2 and Te

Date and Time: 
Thursday, April 30, 2020 - 11:30am
Speaker: 
Dr. Michael T. Pettes
Affiliation: 
Scientist 3, Materials Physics & Applications Division, Los Alamos National Laboratory
Location: 
Discovery Park K110
Abstract: 
Control over disorder arising from nonequilibrium of atomic positions and distributions of mass offers a promising route to design nanomaterial properties for integration into a wide range of existing and future applications. In this talk, I will discuss our recent results on three areas where atomic-scale non-equilibrium and disorder can bring about profound enhancements in both physical and chemical properties, and preview the new imaging techniques that we are developing to establish atomic-level structure-transport property relationships in individual nanomaterials through in-situ transmission electron microscopy. Specific topics include our method to create deterministic single photon emission sites in a WSe2 host, our discovery of the isotope effect in purified 186W80Se2 which is the first report of isotope engineering in a two-dimensional transition metal dichalcogenide (TMD), and structural characterization by large data sets collected using electron microscopy with patterned probes including our observation of strain related torsion in low-dimensional tellurium. These capabilities and discoveries have general implications to defect engineering in the large family of two-dimensional materials and their and hence impact varied and promising technological areas from quantum communication to energy storage and conversion.
Biography: 
Dr. Pettes’ research contributions focus on nanoscale transport experimentation to develop knowledge of emergent phenomena inherent to inorganic nanomaterials. He earned his B.S. in Mechanical Engineering from Duke University in 2001, and his M.S. and Ph.D. in Mechanical Engineering from the University of Texas at Austin in 2007 and 2011, respectively. His research has received recognition by the Department of Energy (LDRD Early Career Research Award 2019), the National Science Foundation (CAREER Award 2016, Graduate Research Fellowship 2006) and National Academy of Engineering (US-EU FOE 2019, FOEE 2016). Pettes’ experimental laboratory is comprised of an ultraviolet confocal Raman, fluorescence, and photoluminescence imaging facility which is available to external collaborators though the DOE NSRC program at CINT (https://cint.lanl.gov/). Website: https://www.lanl.gov/expertise/profiles/view/michael-pettes