Zhao Wei L Z, Tikhonov Konstantin S, Finkel'stein Alexander M
Department of Physics & Astronomy, Texas A&M University, College Station, TX, 77843-4242, USA.
L. D. Landau Institute for Theoretical Physics, 117940, Moscow, Russia.
Sci Rep. 2018 Nov 2;8(1):16256. doi: 10.1038/s41598-018-34426-3.
We identify graphene layer on a disordered substrate as a system where localization of phonons can be observed. Generally, observation of localization for scattering waves is not simple, because the Rayleigh scattering is inversely proportional to a high power of wavelength. The situation is radically different for the out of plane vibrations, so-called flexural phonons, scattered by pinning centers induced by a substrate. In this case, the scattering time for vanishing wave vector tends to a finite limit. One may, therefore, expect that physics of the flexural phonons exhibits features characteristic for electron localization in two dimensions, albeit without complications caused by the electron-electron interactions. We confirm this idea by calculating statistical properties of the Anderson localization of flexural phonons for a model of elastic sheet in the presence of the pinning centers. Finally, we discuss possible manifestations of the flexural phonons, including the localized ones, in the electronic thermal conductance.
我们将无序衬底上的石墨烯层视为一个能够观测到声子局域化的系统。一般来说，观测散射波的局域化并不容易，因为瑞利散射与波长的高次方成反比。对于由衬底诱导的钉扎中心所散射的面外振动，即所谓的弯曲声子，情况则截然不同。在这种情况下，波矢消失时的散射时间趋于一个有限极限。因此，人们可能会预期弯曲声子的物理特性表现出二维电子局域化的特征，尽管没有电子 - 电子相互作用所带来的复杂性。我们通过计算存在钉扎中心时弹性薄片模型中弯曲声子的安德森局域化的统计特性来证实这一想法。最后，我们讨论弯曲声子（包括局域化声子）在电子热导率中的可能表现。
