A Talk on The Quantum and Fractional Quantum Hall Effect was conducted at Amrita Vishwa Vidyapeetham, Amritapuri campus, on January 18, 2017.  Dr. Keyan Bennaceur, l’université Paris, France, was the speaker.

Venue : S10 (conference room, Ground floor, Main building)

About the Speaker

Dr. Keyan worked as a Postdoctoral fellow at Université de Sherbrooke in Pr. B. Reulet’s group (Canada Excellence Research Chair) during 2015-2017. The main focus was on noise and magnetic susceptibility measurement in a 2D electron gas under high magnetic field at very low temperature. Here exotic quantum phases appear such as fractional quantum Hall effect of charge density waves.

He worked as a Postdoctoral fellow at McGill University in Pr. G.Gervais’s group during 2011-2015. His research interest was on Electronic transport at low temperature in 1D and 2D electron system (Fractional quantum Hall effect in AlGaAs, Flip Chip devices, transport in hydrogenated graphene, Quantum Wire in AlGaAs).

2007-2010- He Completed his Ph.D in CEA Saclay on electronic transport in graphene. Here the goal was to fabricate and measure graphene devices at low temperature under a high magnetic field. This work allowed to understand the mechanisms of breakdown of the quantum Hall effect with finite energy.

Abstract of the Talk

The Quantum and Fractional Quantum Hall Effect

Discovered in 1980, by Claus Van Klitzling^[1] and awarded a Nobel prize in 1985, the quantum Hall effect is still one of the most fascinating quantum effect happening in electron transport. It is the quantum version of the Hall effect happening in 2D electron structure such as graphene^[2] or semiconductor heterojunction at very low temperature and high magnetic field. Shortly after, as the fabrication of 2D electron structures improved, the fractional quantum Hall effect ^[3] and electron crystallization^[4] were discovered. In the fractional quantum Hall effect, for which a Nobel prize was awarded in 1998, the interplay of coulomb interaction and the magnetic field gives very unusual properties to the charge carriers such as fractional values for the charge and exotic statistics”. In the seminar, he gave an introduction to the remarkable quantum effects arising in 2D electron structures under magnetic field. Along with this introduction, he also presented their latest results where, by measuring electron noise we have good indications that crystal electronic phase and fractional quantum Hall phase can coexist.

[1] K. v. Klitzing, G. Dorda, and M. Pepper, PRL 45, 494 (1980)

[2] Y Zhang, Y Tan, H. L. Stormer, and P Kim, Nature 438, 201-204 (2005)

[3] D. C. Tsui, H. L. Stormer, and A. C. Gossard PRL 48, 1559 (1982)

[4] A. A. Koulakov, M.M. Fogler, and B. I. Shklovskii, PRL 76, 3, 499 (1996)