A Josephson field effect transistor using an InAs-inserted-channel In0.52Al0.48As/In0.53Ga0.47As inverted modulation-doped structure

Abstract

A Josephson field effect transistor (JOFET) was coupled with a two-dimensional electron gas in a strained InAs quantum well inserted into an In0.52Al0.48As/In0.53Ga0.47As inverted modulation-doped structure. The characteristics of this JOFET are much improved over previous devices by using a high electron mobility transistor (HEMT)-type gate instead of the usual metal-insulator- semiconductor (MIS)-type gate. The superconducting critical current as well as the junction normal resistance are completely controlled via a gate voltage of about −1 V; this provides voltage gain over 1 for a JOFET.

Dynamical selection in developing fermionic pairing

“…The averaging, applied to the initial r p values (24), eliminates the transverse part of (24), containing random phases θ p , while leaving the longitudinal part intact. The Bloch dynamics is unitary with respect to each Bloch vector r p and, in particular, is linear and preserves the norm.…”

“…In the S/Sm/S systems [24,25], the superfluid density and Josephson critical current can be tuned by electric field applied on the gates to the semiconductor. Similarly, the SNS structures [26][27][28] are tunable by current applied to the normal region.…”

“…In Refs. [18,20,21] the picture of time-dependent pairing [5] was extended to the problem of resonant atom-molecule coupling near a Feshbach resonance.Another interesting class of tunable systems are the hybrid semiconductor-superconductor (S/Sm/S) and SNS structures [24][25][26][27][28] with proximity-induced Josephson effect. In the S/Sm/S systems [24,25], the superfluid density and Josephson critical current can be tuned by electric field applied on the gates to the semiconductor.…”

Current-voltage characteristics of semiconductor-coupled superconducting weak links with large electrode separations

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Much of that interest was stimulated by the 1978/1980 papers of Silver et al 17 and Clark et al, 18 who proposed three-terminal gate-modulatable weak-link devices, referred to as hybrid Josephson field effect transistors, or briefly JOFETs. These devices draw on the ability to modulate the electron concentration in a thin semiconductor layer via a gate electrode, and thereby modulate the Josephson critical current.…”

Local suppression of Josephson currents in niobium/two-dimensional electron gas/niobium structures by an injection current

“…1 One approach was to transfer the well-known semiconductor field effect transistor to superconductor/two-dimensional electron gas ͑2DEG͒ structures as proposed by Clark et al 2 The supercurrrent flowing through the 2DEG was switched off by reducing the coherence length in the channel by applying a negative gate voltage. 3,4 Since the voltage necessary for depleting the electrons in the 2DEG channel is typically of the order of the band gap of the semiconductor and the output signal of the order of the superconducting gap of the electrodes, a voltage gain is hard to achieve. An alternative concept to avoid this problem is controlling the supercurrent by the injection of electrons via an additional nonsuperconductive contact into the weak link.…”