Evidence of Lifshitz transition in thermoelectric power of ultrahigh mobility bilayer graphene

Abstract

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.

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Cited by in corpus (7)

• Detecting Lifshitz Transitions Using Nonlinear Conductivity in Bilayer Graphene
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• Quantum Hall interferometry in triangular domains of marginally twisted bilayer graphene
• Excess entropy and breakdown of semiclassical description of thermoelectricity in twisted bilayer graphene close to half filling
• Thermoelectric properties of the Corbino disk in graphene
• Sliding-induced topological transitions in bilayer biphenylene
• Sub-Sharvin conductance and incoherent shot-noise in graphene disks at magnetic field