Anomalously small resistivity and thermopower of strongly compensated semiconductors and topological insulators

Abstract

In the recent paper we explained why the maximum bulk resistivity of topological insulators (TIs)is so small [B. Skinner, T. Chen, and B. I. Shklovskii, Phys. Rev. Lett. 109, 176801 (2012)]. Using the model of completely compensated semiconductor we showed that when Fermi level is pinned in the middle of the gap the activation energy of resistivity $\Delta =0.3(E_g/2)$, where $E_g$ is the semiconductor gap. In this paper, we consider strongly compensated $n$-type semiconductor. We find position of the Fermi level $\mu$ calculated from the bottom of the conduction band and the activation energy of the resistivity $\Delta$ as a function of compensation $K$, and show that $\Delta =0.3(E_c-\mu )$ holds at any $1-K\ll 1$. At the same time Peltier energy (heat) $\Pi$ is even smaller: $\Pi \simeq 0.5\Delta =0.15(E_c-\mu )$. We also show that at low temperatures the activated conductivity crosses over to variable range hopping (VRH) and find the characteristic temperature of VRH, $T_{ES}$, as a function of $1-K$.

References in corpus (17)

• Topological Insulators
• Topological insulators and superconductors
• Topological Insulators in Three Dimensions
• Topological Insulators with Inversion Symmetry
• Topological Field Theory of Time-Reversal Invariant Insulators
• Topological invariants of time-reversal-invariant band structures
• Three dimensional topological invariants for time reversal invariant Hamiltonians and the three dimensional quantum spin Hall effect
• Topological origin of subgap conductance in insulating bilayer graphene
• Two-dimensional Dirac fermions in a topological insulator: transport in the quantum limit
• Bulk Fermi surface coexistence with Dirac surface state in Bi${}_2$Se${}_3$: a comparison of photoemission and Shubnikov-de Haas measurements
• Strong surface scattering in ultrahigh mobility Bi2Se3 topological insulator crystals
• Quantum interference in macroscopic crystals of non-metallic Bi${}_2$Se${}_3$
• Optimizing the Bi_(2-x)Sb_(x)Te_(3-y)Se_(y) solid solutions to approach the intrinsic topological insulator regime
• Angular-dependent oscillations of the magnetoresistance in Bi_2Se_3 due to the three-dimensional bulk Fermi surface
• Fermi level tuning and a large activation gap achieved in the topological insulator Bi_{2}Te_{2}Se by Sn doping
• Why is the bulk resistivity of topological insulators so small?
• Observations of two-dimensional quantum oscillations and ambipolar transport in the topological insulator Bi2Se3 achieved by Cd doping

Cited by in corpus (11)

• Large, nonsaturating thermopower in a quantizing magnetic field
• Gigantic negative magnetoresistance in a disordered topological insulator
• Revealing puddles of electrons and holes in compensated topological insulators
• Charge puddles in the bulk and on the surface of the topological insulator BiSbTeSe${}_2$ studied by scanning tunneling microscopy and optical spectroscopy
• Effect of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators
• Current-induced breakdown of the quantum anomalous Hall effect
• Bi2Te_xSe_y series studied by resistivity and thermopower
• Large enhancement of thermopower at low magnetic field in compensated semimetals
• Enhancement of hopping conductivity by spontaneous fractal ordering of low-energy sites
• Transport properties of band engineered p-n heterostructures of epitaxial Bi${}_2$Se${}_3$/(Bi${}_{1-x}$Sb${}_x$)${}_2$(Te${}_{1-y}$Se${}_y$)${}_3$ topological insulators
• Magnetothermopower of nodal line semimetals