December 13 10:00-11:30 am 

 

Science Building A110

 

Bulk Thermoelectric and Thermodynamic Probes of non-Abelian Anyons in Topological States of Matter

 

Professor Kun Yang

 

National High Magnetic Field Lab and Physics Department, Florida State University, Tallahassee, FL 32306, USA

 

Professor Franck Wilczek showed that anyons obeying fractional statistics may exist in two-dimensions. It is now understood that topological states of matter can indeed support anyon excitations with fractional charge and statistics. Of particular interest are the so called non-Abelian anyons. Most current experimental attempts to reveal non-Abelian fractional statistics focus on interference involving edge transport. After a brief introduction of topological states (mostly in the context of fractional quantum Hall effect) in general, in this colloquium we will discuss how one can reveal the non-Abelian anyon statistics using bulk probes. We show that bulk thermopower is a promising way to detect their non-Abelian nature, and measure the quantum dimension (a key parameter that quantifies non-Abelian statistics) of these anyons [1]. This method is particularly effective in the Corbino geometry [2]. We also demonstrate a novel cooling effect associated with them [3,4]. We discuss application of these ideas to the specific candidate system of fractional quantum Hall liquid at filling factor 5/2 [1,2,3], and topological insulator-superconductor hybrid systems [4]. Some of the predicted behavior has been observed in recent experiments [5,6], which will also be discussed. This body of work has also motivated further theoretical efforts of using thermal probes to study non-Abelian anyons [7].

 

[1] Kun Yang and B. I. Halperin, Phys. Rev. B 79, 115317 (2009).

[2] Y. Barlas and Kun Yang, Phys. Rev. B 85, 195107 (2012).

[3] G. Gervais and Kun Yang, Phys. Rev. Lett. 105, 086801 (2010).

[4] S. Yamamoto, M. Freedman, and Kun Yang, Phys. Rev. B 84, 104503 (2011).

[5] W. E. Chickering, J. P. Eisenstein, L. N. Pfeiffer, and K. W. West, Phys. Rev. B 87, 075302 (2013).

[6] Shuhei Kobayakawa, Akira Endo, and Yasuhiro Iye, J. Phys. Soc. Jpn. 82, 053702 (2013).

[7] N. d’Ambrumenil and R. H. Morf, Thermopower in the Quantum Hall Regime, Phys. Rev. Lett. 111, 136 (2013); Chang-Yu Hou, Y. Barlas, K. Shtengel, Adiabatic cooling of Majorana zero-modes in topological superconductors, eprint arXiv:1310.1418.