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Wednesday, August 13 • 10:20 - 12:20
IUPAP Young Scientist Award Session

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Invited: Xiaodong Xu
Spin & Pseudospins in 2D Semiconductors
Co-authors: Galan Moody, Sanfeng Wu, Yanwen Wu, Nirmal Ghimire, Jiaqiang Yan, David Mandrus, Xiaoqin Li

Electronic valleys are extrema of Bloch energy bands in momentum space. Having multiple valleys gives the electron states pseudospin degrees of freedom in addition to their real spin. In this talk, I will discuss our experimental progress on the investigation of spins and pseudospins using atomically thin semiconductors, which are either single or bilayer group VI transition metal dichalcogenides. These new 2D semiconductors behave as remarkable excitonic systems, providing an exciting laboratory for optical manipulation and electrical control of the valley degrees of freedom. I will also discuss strong coupling effects between spin, valley, and layer pseudo-spins in bilayers, which lead to enhanced lifetimes and allow electrical control of spin states.

Co-authors: Galan Moody, Sanfeng Wu, Yanwen Wu, Nirmal Ghimire, Jiaqiang Yan, David Mandrus, Xiadong Xu, Xiaoqin Li

Invited: Rahul Raveendran Nair
Novelties in Two Dimensions

In my talk, I will mainly discuss the novel properties of various two dimensional materials. Graphene, the first discovered two dimensional crystal, continues to attract intense interest that has expanded into research areas beyond the initial studies of graphene’s electronic transport properties. Here, I will discuss the structural, optical and electronic properties of graphene and other two dimensional materials derived from graphene. Second part of my talk will focus the magnetic properties of graphene. I will review our recent experiments on inducing and controlling magnetic response in graphene. Graphene is hailed as potentially an ideal material for spintronics due to its weak spin-orbit interaction and the ability to control its electronic properties by the electric field effect. We show that, despite the absence of d- or f- electrons normally associated with magnetism, it is possible to induce magnetic response in graphene via introduction of point defects such as vacancies and adatoms. We have demonstrated that both vacancies and adatoms in graphene carry magnetic moments, leading to pronounced paramagnetic behaviour that dominates its low-temperature magnetism. Even better, we show that the defect magnetism is itinerant (i.e. due to localisation of conduction electrons) and can be controlled by doping, so that the induced magnetic moments can be switched on and off. This not only adds important functionality to potential graphene devices but also has important implications for spin transport. 



Session Chairs

Mike L. W. Thewalt

Professor, Simon Fraser University
Michael L. W. Thewalt is a Canadian physicist. He received his BSc from McMaster University in 1972. His MSc and PhD were from the University of British Columbia in the mid-1970s. He teaches at Simon Fraser University and is known for researching semiconductors, especially isotopically enriched silicon.


Rahul Raveendran Nair

Leverhulme Fellow, School of Physics & Astronomy, The University of Manchester
Dr. R. R. Nair received his PhD from the University of Manchester in 2010. Currently he is a member of academic staff in the School of Physics and Astronomy at the University of Manchester. In 2012 he was awarded a prestigious Leverhulme Research Fellowship and will take up a 5-year Royal Society University Research Fellowship from October 2014. He is an expert in optical, magnetic and membrane properties of graphene and other 2D... Read More →

Xiaodong Xu

Assistant Professor, Department of Physics & MSE, University of Washington
Xiaodong Xu joins the Materials Science & Engineering in the fall of 2010 from Cornell University, where he was a postdoctoral research associate. | | Xu's research interests focus on optoelectronic, spintronic, and photovoltaic applications of carbon-based nanomaterials. Spin-based electronics (spintronics) has made a huge impact on memory storage systems. Xu's work contributes to the goal of miniaturizing spintronics to the level of a... Read More →

Wednesday August 13, 2014 10:20 - 12:20
Room 16B

Attendees (12)