#### Condensed Matter Seminar, Liang Fu, MIT, From Topological Crystalline Insulator to Anderson Transition

Structure and symmetry play important roles in determining electronic properties of periodic solids. The interplay between crystalline symmetry and electronic topology leads to new phases of matter dubbed topological crystalline insulators, which possess protected surface states with unique and tunable electronic properties.

In this talk, I will describe theoretical prediction of topological crystalline insulators in the SnTe class of IV-VI semiconductors, and experimental observation of topological

surface states.

The robustness of such surface states against strong disorder has motivated a re-examination of theory of Anderson localization. I will describe a new field theory for Anderson transition in the two-dimensional symplectic class, in which topological defects drive localization and the sign of defect fugacity determines the topological class of the localized phase. This leads to a unifying picture that all metal-insulator transitions in two dimensions are topological phase transitions.

References:

[1] L. Fu, Phys. Rev. Lett. 106, 106802 (2011).

[2] T. H. Hsieh, H. Lin, J. Liu, W. Duan, A. Bansil, and L. Fu, Nat. Commun., 3, 982 (2012).

[3] L. Fu and C. L. Kane, Phys. Rev. Lett. 109, 246605 (2012).

**Location:**
PCTS Seminar Room

**Date/Time: **05/13/13
at
1:15 pm
- 05/13/13
at
2:30 pm

**Category: **Condensed Matter Seminar

**Department: **Physics