Impact of Heterostructure Design on Transport Properties in the Second Landau Level of in-situ Back-Gated Two-Dimensional Electron Gases

Abstract

We report on transport in the second Landau level in \emph{in-situ} back-gated two-dimensional electron gases in GaAs/Al${}_x$Ga${}_{1-x}$As quantum wells. Minimization of gate leakage is the primary heterostructure design consideration. Leakage currents resulting in dissipation as small as $\sim$ 10 pW can cause noticeable heating of the electrons at 10 mK, limiting the formation of novel correlated states. We show that when the heterostructure design is properly optimized, gate voltages as large as 4V can be applied with negligible gate leakage, allowing the density to be tuned over a large range from depletion to over 4 $\times$ 10${}^{11}$ cm${}^{-2}$. As a result, the strength of the $\nu =5/2$ state can be continuously tuned from onset at n $\sim 1.2\times 10^{11}$ cm${}^{-2}$ to a maximum ${\Delta }_{5/2}=625$ mK at n = $3.35\times 10^{11}$ cm${}^{-2}$. An unusual evolution of the reentrant integer quantum Hall states as a function of density is also reported. These devices can be expected to be useful in experiments aimed at proving the existence of non-Abelian phases useful for topological quantum computation.

Re-ordered sections, added schematic of device design. 8 pages, 9 figures

References in corpus (8)

• Non-Abelian Anyons and Topological Quantum Computation
• Particle-hole symmetry and the Pfaffian state
• Particle-Hole Symmetry and the $\nu =5/2$ Quantum Hall State
• Finite Layer Thickness Stabilizes the Pfaffian State for the 5/2 Fractional Quantum Hall Effect: Wavefunction Overlap and Topological Degeneracy
• The non-Abelian Interferometer
• Experimental probe of topological orders and edge excitations in the second Landau level
• Mobility versus quality in 2D semiconductor structures
• Low-temperature illumination and annealing of ultra-high quality quantum wells

Cited by in corpus (4)

• Microwave-induced resistance oscillations in a back-gated GaAs quantum well
• Observation of flat bands in gated semiconductor artificial graphene
• Hall field-induced resistance oscillations in a tunable-density GaAs quantum well
• Effect of density on microwave-induced resistance oscillations in back-gated GaAs quantum wells