Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nat Commun. 2012;3:1239. doi: 10.1038/ncomms2243.
The advent of few-layer graphene has given rise to a new family of two-dimensional systems with emergent electronic properties governed by relativistic quantum mechanics. The multiple carbon sublattices endow the electronic wavefunctions with pseudospin, a lattice analogue of the relativistic electron spin, whereas the multilayer structure leads to electric-field-effect tunable electronic bands. Here we use these properties to realize giant conductance oscillations in ballistic trilayer graphene Fabry-Pérot interferometers, which result from phase coherent transport through resonant bound states beneath an electrostatic barrier. We confine these states by selectively decoupling them from the leads, resulting in transport via non-resonant states and suppression of the giant oscillations. The confinement is achieved both classically, by manipulating quasiparticle momenta with a magnetic field, and quantum mechanically, by locally varying the pseudospin character of the carrier wavefunctions. Our results illustrate the unique potential of trilayer graphene as a versatile platform for electron optics and pseudospintronics.
少层石墨烯的出现催生了一类新的二维体系，其电子性质由相对论量子力学所支配。多个碳原子亚晶格赋予了电子波函数赝自旋，这是相对论电子自旋的晶格类似物，而多层结构则导致了电场效应可调谐的电子能带。在这里，我们利用这些性质在弹道三层石墨烯法布里-珀罗干涉仪中实现了巨大的电导振荡，这是由于静电势垒下通过共振束缚态的相干输运而产生的。我们通过选择性地将这些态与引线解耦来限制这些态，从而导致通过非共振态的输运和对巨大振荡的抑制。这种限制既可以通过磁场操纵准粒子动量来实现经典限制，也可以通过局部改变载流子波函数的赝自旋特性来实现量子限制。我们的结果说明了三层石墨烯作为电子光学和赝自旋电子学的多功能平台的独特潜力。
