University of Cambridge > Talks.cam > Theory of Condensed Matter > Topological electronic properties of silicon

Topological electronic properties of silicon

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Bartomeu Monserrat.

The central role that materials play in human history is exemplified by the three-age division of prehistory into the stone, bronze, and iron ages. References to our present time as the information age or silicon age epitomizes the important role that this semiconducting material came to play in the development of computers and devices that permeate our daily lives. Remarkably, silicon has been left out of the explosion of research activity on topological materials. On the surface, this omission is the result of a boundary-centric classification of undoped silicon as a “trivial insulator”. Here we show that the electronic states in silicon have nontrivial topological structures that are captured by a network of Berry flux lines that link at points of high symmetry in the Brillouin zone. This complex network has ice-nodal points where fluxes satisfy ice rules. Fixing the longitudinal momentum parallel to such flux lines yields a two-dimensional Dirac Hamiltonian for the transverse degrees of freedom. This complex Berry-flux network implies a topologically stable two-fold degeneracy along the X-W direction in all of silicon bands, a fact that is supported by crystal symmetry arguments as well as direct inspection of the vast literature on silicon band structures.

This talk is part of the Theory of Condensed Matter series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

 

© 2006-2019 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity