Radiation-Induced “Zero-Resistance State” and the Photon-Assisted Transport

We demonstrate that the radiation-induced “zero-resistance state” observed in a two-dimensional electron gas is a result of the nontrivial structure of the density of states of the systems and the photon-assisted transport. A toy model of a quantum tunneling junction with oscillatory density of states in leads catches most of the important features of the experiments. We present a generalized Kubo-Greenwood conductivity formula for the photon-assisted transport in a general system and show essentially the same nature of the transport anomaly in a uniform system.

Figure 1

Toy model of a quantum tunneling junction. A dc voltage $V$ and an ac field $V_{\mathrm{a}\mathrm{c}}=\Delta \cos \omega t$ are applied on a quantum tunneling junction.

Figure 2

Conductance dependence on $1/{\omega }_c$ for different radiation intensities. The parameters are the same as those used in Ref. 4: $\mu =50\hslash \omega$, $kT=0.25\hslash \omega$, $\omega {\tau }_f=6.25$.

Figure 3

(a) Charge buildup in the negative conductance regime at a constant voltage measurement. (b) Instability in a constant voltage measurement. (c) Bistability in a constant current measurement.