The electronic transport of top subband and disordered sea in an InAs nanowire in the presence of a mobile gate

Abstract

We performed measurements at helium temperatures of the electronic transport in an InAs quantum wire (R(wire) ∼ 30 kΩ) in the presence of a charged tip of an atomic force microscope serving as a mobile gate. The period and the amplitude of the observed quasi-periodic oscillations are investigated in detail as a function of electron concentration in the linear and non-linear regime. We demonstrate the influence of the tip-to-sample distance on the ability to locally affect the top subband electrons as well as the electrons in the disordered sea. Furthermore, we introduce a new method of detection of the subband occupation in an InAs wire, which allows us to evaluate the number of electrons in the conductive band of the wire.

Investigations of local electronic transport in InAs nanowires by scanning gate microscopy at liquid helium temperatures

“…4 in [26], than the main dependence of 1/R wire (V BG ) is linear. Aperiodic deviations of this main dependence with character size of ∼ 0.1(e 2 /h) are usually attribute to universal conductance fluctuations (UCF) [7,35].…”

“…The reason for it is clear, the distance of 250-300 nm in between electrons for V C ∼ k B T is close to l cut and also this length is comparable to the resolution of our experimental setup of ∼ 150 − 200 nm. Taking into account the scale of kinetic energy for N node = 2 mentioned previously, the investigation of the stability of the observed structure looks rather important [26]. The resulting experimental data is presented in Fig.…”

“…The resulting experimental data is presented in Fig. 2 in [26]. No significant deviations of the node positions and the amplitude of the oscillations are found as long as eV SD ≤ k B T .…”

“…3d) to f) in [26] changes essentially when V BG rises just for 20 mV while SGM images are obtained with scanning tip placed close to the nanowire (l tip ∼ d), here d is the wire diameter. In contrast to that, the width of the step as a function of l node (V BG ) is more than hundred millivolts.…”

“…Thus, a wide range of scenarios from closed sequentially connected quantum dots demonstrating Coulomb blockade to metallic diffusive wire are realized and investigated. Special attention is devoted to induced negative differential conductance (NDC) [24] and recently observed quasiperiodic oscillations [25,26].…”