カーボンナノチューブコミュの多層グラフェンの電子特性越野幹人氏（東工大理）

Date: October 16, 2008 (Thursday)
Time: 14:00 -
Place: Seminar Room D821, Tsukuba Central 2, AIST

Title: Electronic properties of graphene multilayers
多層グラフェンの電子特性

Speaker: Dr. Mikito Koshino (Tokyo Institute of Techonology)
越野幹人氏（東工大理）

Abstract:
Since the recent experimental realization of atomically thin graphene films, the graphene multilayers
have attracted broad interest as well as monolayer. Here we study the band　structure and the　
electronic properties of few-layered graphenes　using the effective mass approximation.　We show
that, in general multilayer graphenes with any numbers of layers,　the effective mass Hamiltonian
can be decoupled into sub-Hamiltonians equivalent to monolayer or bilayer, and the physical
quantities can be calculated by summing up contributions of every sub-systems. When the number of
layers N is odd, the system has one effective monolayer and (N-1)/2 bilayers, while when N is even,
it has just N/2 bilayers but no monolayers. Based on this model, we study the magneto-optical
absorption and the orbital diamagnetism of multilayer graphenes. We show that the monolayer-type
subband,
which exists only in the odd-layered graphenes, presents a characteristic feature and makes a
difference between odd and even layers.