论文标题
通过激光场下的垂直石墨烯触点进行运输
Transport through vertical graphene contacts under intense laser fields
论文作者
论文摘要
从理论上讲，我们研究了两个石墨烯层的电子和传输特性，该层在时间周期性外部光场的影响下由绝缘层垂直耦合。非绝热驱动会引起电子的激发和被占用状态的重新分布，这表现在石墨烯的准烯类频谱中的间隙开放中。当顶部和底部石墨烯层之间施加电压时，光诱导的非平衡职业会修改触点的传输特性。我们使用非平衡绿色的功能形式主义研究了接触的电子和传输特性。为了说明在光照射下垂直接触的差分电导的行为，我们考虑了两种情况。首先，我们假设底层和顶层由石墨烯组成，其次我们考虑底层中的有限质量项。我们得到的是，由于石墨烯中的准谱光谱中的间隙打开，差异电导被强烈抑制。此外，电导显示的特征与范霍夫奇异性的能量相对应的光激发电子的隧道，用于顶层和底层。在底层有限的质量项的情况下，差分电导可以与光激发电子的隧道直接相关。
We theoretically study the electronic and transport properties of two graphene layers vertically coupled by an insulating layer under the influence of a time-periodic external light field. The non-adiabatic driving induces excitations of electrons and a redistribution of the occupied states which is manifested in the opening of gaps in the quasienergy spectrum of graphene. When a voltage is applied between the top and bottom graphene layers, the photo-induced nonequilibrium occupation modifies the transport properties of the contact. We investigate the electronic and transport properties of the contact by using the nonequilibrium Green's function formalism. To illustrate the behavior of the differential conductance of the vertical contact under the light illumination, we consider two cases. First, we assume that both the bottom and top layers consist of graphene and second we consider a finite mass term in the bottom layer. We obtain that the differential conductance is strongly suppressed due to the opening of gaps in the quasienergy spectrum in graphene. Additionally, the conductance shows features corresponding to the tunneling of photoexcited electrons at energies of the van Hove singularity for both the top and bottom layers. In the case of a finite mass term in the bottom layer, the differential conductance can be directly related to the tunneling of photoexcited electrons.
