本文报道了GaAs/Al $_x$ Ga $_{1-x}$ As量子阱中\emph{in-situ}背栅二维电子气的朗道第二能级输运。最小化栅极泄漏是异质结构设计的主要考虑因素。漏电流导致的耗散小至$\sim$ 10 pW，可导致10 mK下电子的明显加热，限制了新相关态的形成。我们表明，当异质结构的设计进行了适当的优化，栅极电压高达4V，可以忽略不计的栅极泄漏，允许的密度被调谐在一个很大的范围从耗尽超过4 $\times$-10 $^{11}$ cm $^{-2}$。结果，$ν= 5/2$状态的强度可以从在n $\sim 1.2 \times 10^{11}$ cm $^{-2}$处的开始连续地调谐到在n = $3.35 \times 10^{11}$ cm $^{-2}$处的最大$Δ_{5/2} = 625$ mK。一个不寻常的演变的可重入整数量子霍尔态作为密度的函数。这些设备可以预期是有用的实验，旨在证明拓扑量子计算有用的非阿贝尔相位的存在。
英文摘要：
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 $ν= 5/2$ state can be continuously tuned from onset at n $\sim 1.2 \times 10^{11}$ cm$^{-2}$ to a maximum $Δ_{5/2} = 625$ 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.
In-situ Raman Spectroscopy of the Graphene / Water Interface of a Solution-Gated Field Effect Transistor: Electron-Phonon Coupling and Spectroelectrochemistry
