Youngwook Kim (PHYS Ph.D. candidate) and Seung-Geol Nam (PHYS M.S.-Ph.D. integrated) observed breakdown of the interlayer coherence in twisted bilayer graphene. Laboratory for Advanced Materials and Extreme Conditions (AMEX) confirmed that in the case of twisted bilayer graphene, despite interlayer distance is atomic length scale, the interlayer coherence breaks up at low temperature.
This result runs counter to existing understanding that interlayer coherence in layer structure is mainly determined by interlayer distance. In addition, research also confirmed that although interlayer conducting property is sensitive to twisted angle at low temperatures, angle dependence is relaxed due to phonon-mediated interlayer conduction at high temperature.
This result is expected to provide basic information for developing devices using the junction of graphene atomic layer. The paper is published in Physical Review Letters Volume 110, Issue 9 on Feb. 27, 2013.