Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Max Planck-POSTECH/Hsinchu Center for Complex Phase Materials. Max Plank POSTECH/Korea Research Initiative (MPK) , Gyeongbuk 37673, South Korea.
Nano Lett. 2017 Oct 11;17(10):5914-5918. doi: 10.1021/acs.nanolett.7b01650. Epub 2017 Sep 18.
The electron band structure of graphene on SrTiO substrate has been investigated as a function of temperature. The high-resolution angle-resolved photoemission study reveals that the spectral width at Fermi energy and the Fermi velocity of graphene on SrTiO are comparable to those of graphene on a BN substrate. Near the charge neutrality, the energy-momentum dispersion of graphene exhibits a strong deviation from the well-known linearity, which is magnified as temperature decreases. Such modification resembles the characteristics of enhanced electron-electron interaction. Our results not only suggest that SrTiO can be a plausible candidate as a substrate material for applications in graphene-based electronics but also provide a possible route toward the realization of a new type of strongly correlated electron phases in the prototypical two-dimensional system via the manipulation of temperature and a proper choice of dielectric substrates.
已研究 SrTiO 衬底上石墨烯的电子能带结构随温度的变化。高分辨率角分辨光发射研究表明，SrTiO 上石墨烯的费米能处谱线宽度和费米速度可与 BN 衬底上石墨烯的谱线宽度和费米速度相媲美。在接近电中性时，石墨烯的能量-动量色散明显偏离熟知的线性关系，且随着温度降低而放大。这种修正类似于增强电子-电子相互作用的特征。我们的研究结果不仅表明 SrTiO 可能成为基于石墨烯电子学应用的理想衬底材料，而且还为通过温度控制和合适的介电衬底选择在原型二维系统中实现新型强关联电子相提供了一种可能途径。
