Ambipolar Surface State Thermoelectric Power of Topological Insulator Bi2Se3

Abstract

We measure gate-tuned thermoelectric power of mechanically exfoliated Bi2Se3 thin films in the topological insulator regime. The sign of the thermoelectric power changes across the charge neutrality point as the majority carrier type switches from electron to hole, consistent with the ambipolar electric field effect observed in conductivity and Hall effect measurements. Near charge neutrality point and at low temperatures, the gate dependent thermoelectric power follows the semiclassical Mott relation using the expected surface state density of states, but is larger than expected at high electron doping, possibly reflecting a large density of states in the bulk gap. The thermoelectric power factor shows significant enhancement near the electron-hole puddle carrier density ~ 0.5 x 1012 cm-2 per surface at all temperatures. Together with the expected reduction of lattice thermal conductivity in low dimensional structures, the results demonstrate that nanostructuring and Fermi level tuning of three dimensional topological insulators can be promising routes to realize efficient thermoelectric devices.

References in corpus (24)

• Topological Insulators in Three Dimensions
• Electronic transport in two dimensional graphene
• First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
• Charged Impurity Scattering in Graphene
• Crossover of Three-Dimensional Topological Insulator of Bi2Se3 to the Two-Dimensional Limit
• A self-consistent theory for graphene transport
• Thermoelectric and Magnetothermoelectric Transport Measurements of Graphene
• p-type Bi2Se3 for topological insulator and low temperature thermoelectric applications
• Electronic transport in graphene: A semi-classical approach including midgap states
• Anomalous thermoelectric transport of Dirac particles in graphene
• Strong surface scattering in ultrahigh mobility Bi2Se3 topological insulator crystals
• Surface conduction of topological Dirac electrons in bulk insulating Bi2Se3
• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
• The thermopower and Nernst Effect in graphene in a magnetic field
• Modulation of Thermoelectric Power of Individual Carbon Nanotubes
• In-plane transport and enhanced thermoelectric performance in thin films of the topological insulators Bi_2Te_3 and Bi_2Se_3
• Rashba spin-splitting control at the surface of the topological insulator Bi2Se3
• Slow imbalance relaxation and thermoelectric transport in graphene
• Theory of thermopower in 2D graphene
• First Principles Investigations of the Atomic, Electronic, and Thermoelectric Properties of Equilibrium and Strained Bi2Se3 & Bi2Te3, with van der Waals Interactions
• Impurity Scattering and Mott's Formula in Graphene
• Intrinsic Electron-Phonon Resistivity in Bi2Se3 in the Topological Regime
• Holey topological thermoelectrics
• Thermoelectric effect in high mobility single layer epitaxial graphene

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• Colloquium: Topological Band Theory
• Topological quantum materials from the viewpoint of chemistry
• Probing topological insulators surface states via plasma-wave Terahertz detection
• Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation By Inelastic Scattering
• Gate-Tunable and Thickness-dependent Electronic and Thermoelectric Transport in few-layer MoS2
• Giant thermoelectric effect in graphene-based topological insulators with nanopores
• Propagation of Surface Plasmon Polaritons in Thin Films of Topological Insulators
• Pressure-induced phase transition in Bi${}_2$Se${}_3$ at 3 GPa: electronic topological transition or not?
• Chemical Potential Fluctuations in Topological Insulator (Bi${}_{0.5}$Sb${}_{0.5}$)${}_2$Te${}_3$ Films Visualized by Photocurrent Spectroscopy
• Coulomb drag in topological insulator films
• Coulomb drag in topological materials
• From classical to quantum regime of topological surface states via defect engineering
• Thermoelectric refrigerator based on asymmetric surfaces of a magnetic topological insulator