Abstract: In van der Waals bilayers, the strict requirement of lattice matching at the interface is lifted. The periodic changes in atomic alignment lead to the formation of an in-plane superlattice, known as the moiré superlattice. The twist angle controls the size of the moiré supercells and acts as a unique knob to control the material properties. While many electronic phases (e.g. superconductivity and orbital magnetism) have been discovered at low temperatures, other aspects of such moiré crystals remain to be explored. In this talk, I will discuss how atomic reconstructions of the moiré pattern change with the twist angle and how one can probe it using simple Raman spectroscopy. Other excited state properties such as exciton lifetime and diffusion are also drastically modified with a subtle change in the twist angle.
Bio: Xiaoqin Elaine Li received her B.S degree from Beijing Normal University in 1997 and Ph.D. in physics in 2003 from the University of Michigan. She was a postdoc fellow at JILA, Colorado from 2003-2006. She started as an assistant professor at UT-Austin in 2007 and was promoted to full professor in 2018. Prof. Li has received several awards including the Presidential Early Career Award for Scientists and Engineers in the U. S. and a Sloan Fellowship. She was a Humboldt research fellow at the Technical University of Berlin between 2013-2015. She is a fellow of the American Physics Society. During the pandemic, she started a guided summer reading program on the popular science book “Physics for Future Presidents” for high school students.
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2020-12-17T14:00:002020-12-17T15:00:00CM Seminar - Twist angle control of moiré superlattice properties Event Information:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting code: 657 8412 2083
Passcode: 113399
Abstract: In van der Waals bilayers, the strict requirement of lattice matching at the interface is lifted. The periodic changes in atomic alignment lead to the formation of an in-plane superlattice, known as the moiré superlattice. The twist angle controls the size of the moiré supercells and acts as a unique knob to control the material properties. While many electronic phases (e.g. superconductivity and orbital magnetism) have been discovered at low temperatures, other aspects of such moiré crystals remain to be explored. In this talk, I will discuss how atomic reconstructions of the moiré pattern change with the twist angle and how one can probe it using simple Raman spectroscopy. Other excited state properties such as exciton lifetime and diffusion are also drastically modified with a subtle change in the twist angle.
Bio: Xiaoqin Elaine Li received her B.S degree from Beijing Normal University in 1997 and Ph.D. in physics in 2003 from the University of Michigan. She was a postdoc fellow at JILA, Colorado from 2003-2006. She started as an assistant professor at UT-Austin in 2007 and was promoted to full professor in 2018. Prof. Li has received several awards including the Presidential Early Career Award for Scientists and Engineers in the U. S. and a Sloan Fellowship. She was a Humboldt research fellow at the Technical University of Berlin between 2013-2015. She is a fellow of the American Physics Society. During the pandemic, she started a guided summer reading program on the popular science book “Physics for Future Presidents” for high school students. Event Location:
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