论文标题
超高迁移率双层石墨烯的热电功率中的LIFSHITZ过渡的证据
Evidence of Lifshitz transition in thermoelectric power of ultrahigh mobility bilayer graphene
论文作者
论文摘要
解决状态密度（DOS）中的低能特征是理解基于石墨烯的2D异质结构中各种各样的丰富新现象的关键。由三角翘曲引起的双层石墨烯（BLG）中的LIFSHITZ过渡已在理论上和实验中建立。然而，由于其能量量表相对较低（$ \ sim 1 $ MEV），其对运输特性的影响的实验实现一直具有挑战性。在这项工作中，我们证明了热电功率（TEP）可用作研究BLG DOS的细微变化的有效探针。我们观察到Gapped BLG中电荷中性点（CNP）附近的其他熵特征。可以通过考虑三角翘曲的影响来定量地解释这种明显的违反莫特公式的行为，从而作为Lifshitz过渡的可能证据。
Resolving low-energy features in the density of states (DOS) holds the key to understanding wide variety of rich novel phenomena in graphene based 2D heterostructures. Lifshitz transition in bilayer graphene (BLG) arising from trigonal warping has been established theoretically and experimentally. Nevertheless, the experimental realization of its effects on the transport properties has been challenging because of its relatively low energy scale ($\sim 1$ meV). In this work, we demonstrate that the thermoelectric power (TEP) can be used as an effective probe to investigate fine changes in the DOS of BLG. We observe additional entropy features in the vicinity of the charge neutrality point (CNP) in gapped BLG. This apparent violation of Mott formula can be explained quantitatively by considering the effects of trigonal warping, thereby serving as a possible evidence of a Lifshitz transition.
