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Dr. Ivan Naumov

Geophysical Laboratory, Carnegie Institution of Sciences, 5251 Broad Branch Road, Washington DC 20015 

March 19, 3:30 PM

Thirkield Hall (Physics), room 103

 

Topological phases:  from topological insulators to compressed hydrogen and alkali metals

The recently established concept of “topological phases” refers to the materials with a nontrivial bulk-edge/surface correspondence of topological nature. In the context of solid state physics, such phases include quantum Hall insulators, topological insulators, topological semimetals, etc. In my talk, I will first review the theoretical foundation for different topological phases. I will discuss my recent results proving
that compressed hydrogen and alkali metals can also be viewed as topological phases under some conditions. I will show that both
dense hydrogen and insulating forms of alkali metal (or high-pressure “electrides”) have metallic surfaces that are controlled by the topology of the bulk band structure; i.e., they are topological phases. Such surface-states appear inside the bulk “direct” gap in the two-dimensional surface Brillouin zone.

 

 

Refreshments will be served at 3:15pm