[SAINT] Special lecture

Dr. Dong Su Lee (KIST)

Sungkyunkwan University invites Dr. Dong Su Lee, to hold a special lecture. We'd appreciate it if you could attend.

• Lecturer: Dr. Dong Su Lee (Max Planck Institute for Solid State Research, Stuttgart, Germany & Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST))
• Topic: Tran conductance fluctuations as a probe for interaction-induced quantum Hall states in grapheme
• Date: 14 June, 2012 (THU) 16:00 - 17:00
• Location: #83188, Research Complex 2, Natural Science Campus (Suwon), Sungkyunkwan University
• Contact: Office of SAINT (031-299-4115)
• Summary :
  Transport measurements normally provide a macroscopic, averaged view of the sample, so that disorder
  frequently prevents the observation of fragile interaction induced states in the conductance. In the quest for
  observing fragile or novel incompressible states in graphene, therefore, probing a smaller area may be a way
  to circumvent the challenges of producing high mobility samples, since the sample may be much cleaner on
  the nanometer scale. However, to obtain such microscopic information we are usually forced to resort to
  sophisticated local probe methods. Here, we note that graphene magnetotransport traces are frequently
  cluttered with fluctuations and demonstrate that these fluctuations reflect processes that occur very locally.
  They are a manifestation of charge localization [1, 2] and are more pronounced in the transconductance. A
  systematic study allows observing higher order fractional quantum Hall states in the Hall or longitudinal
  resistance traces [3]. They make phenomena on the nanometer scale visible in macroscopic transport
  experiment despite significant disorder. The fluctuations appear when conduction channels are influenced by
  the compressible quantum dots which form near incompressible quantum states. The presence of a network
  of the dots is proved directly in transport near zero filling where all regular transport channels are turned off
  and a true quantum Hall insulating state develops.