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Event Detail Information

Event Detail Information

Speaker Prof. Jerome Cayssol - University of California - Berkeley
Date Apr 16, 2012
Time 12:00 pm  
Location 190 Engineering Sciences Building
Contact Sue Lynn Herdle
Phone 244-1553
Event type ICMT Seminar
Views 1507
We have shown that deformed honeycomb lattices are promising platforms to realize fractional topological quantum states in the absence of any magnetic field [1]. The strained induced pseudo magnetic fields are oppositely oriented in the two valleys and can be as large as 60-300 T as reported in recent experiments [2,3]. For strained grapheme at neutrality, we predict either a spin or valley polarized state depending on the value of the onsite Coulomb interactions. At fractional filling, the unscreened Coulomb interaction leads to a Fractional Quantum Hall liquid, which spontaneously breaks time reversal symmetry. This robust valley polarized state can be destabilized towards a valley symmetric state (valley fractional topological insulator) by tuning the short range part of Coulomb interactions. A spin triplet superconductor is also realized in this flat band system in presence of attractive local interactions. The importance of interaction engineering to realize these phas es points to new directions for future research both in real [2] and artificial [3,4] graphenes. [1] P. Ghaemi, J. Cayssol, D.N. Sheng, and A. Vishwanath, arXiv:1111.3640 [2] L. Levy and al., Science 329, 544 (2010). [3] K.K. Gomes and al., Nature 483, 306 (2012). [4] l. Tarruell and al., Nature 483, 302 (2012).