IEEE Photonics Society

Boston Photonics Society Chapter

Boston Chapter of the IEEE Photonics Society

Machine Learning and Optical Systems

Wednesday, October 7, 14, 21, 28 and November 4, 2020, 7:00-9:30 PM
Location: Online Seminar

October 14, 2020
7 PM

Online Seminar

Deep Elastic Strain Engineering of Band Structure through Machine Learning Video

Prof. Ju Li, Massachusetts Institute of Technology, Cambridge, MA


Prof. Ju Li, Massachusetts Institute of Technology, Cambridge, MA

Abstract:  Nanoscale specimens of semiconductor materials as diverse as silicon and diamond are now known to be deformable to large elastic strains without inelastic relaxation. These discoveries harbinger a new age of deep elastic strain engineering of the band structure and device performance of electronic materials. Many possibilities remain to be investigated as to what pure silicon can do as the most versatile electronic material and what an ultrawide bandgap material such as diamond, with many appealing functional figures of merit, can offer after overcoming its present commercial immaturity. Deep elastic strain engineering explores full six-dimensional space of admissible nonlinear elastic strain and its effects on physical properties. Here we present a general method that combines machine learning and ab initio calculations to guide strain engineering whereby material properties and performance could be designed. This method invokes recent advances in the field of artificial intelligence by utilizing a limited amount of ab initio data for the training of a surrogate model, predicting electronic bandgap within an accuracy of 8 meV. Our model is capable of discovering the indirect-to-direct bandgap transition and semiconductor-to-metal transition in silicon by scanning the entire strain space. It is also able to identify the most energy-efficient strain pathways that would transform diamond from an ultrawide-bandgap material to a smaller-bandgap semiconductor. A broad framework is presented to tailor any target figure of merit by recourse to deep elastic strain engineering and machine learning for a variety of applications in microelectronics, optoelectronics, photonics, and energy technologies.


Biography:  Ju Li has held faculty positions at the Ohio State University, the University of Pennsylvania, and is presently a chaired professor at MIT.  His group ( investigates the mechanical, electrochemical and transport behaviors of materials as well as novel means of energy storage and conversion. Ju is a recipient of the 2005 Presidential Early Career Award for Scientists and Engineers, the 2006 Materials Research Society Outstanding Young Investigator Award, and the TR35 award from Technological Review. Ju was elected Fellow of the American Physical Society in 2014 and a Fellow of the Materials Research Society in 2017. In 2014,18,19 Thomson Reuters/Clarivate included him in the Highly Cited Researchers list in Materials Science category. In 2016 Ju Li co-founded one of the MIT Energy Initiative (MITEI) Low-Carbon Energy Centers, the Center for Materials in Energy and Extreme Environments (CME).


Advance registration required, but there is no fee (Open to all IEEE members as well as non-members)

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The workshop expenses have
been generously supported by:



For more information on the technical content of the workshop, contact either:
1) Keisuke Kojima, (, Chair
2) Ajay Garg, (, Co-Chair
3) Dean Tsang, (, Co-Chair
4) Bill Nelson, (, Co-Chair