47 citations · 232 across the 16 of their papers we have counts for
16 papers
Formation of tungsten carbide by focused ion beam process: A route to high magnetic field resilient patterned superconducting nanostructures
Himadri Chakraborti, Bhanu P Joshi, Chanchal K. Barman +10
A scale for magnetic field resilience of a superconductor is set by the paramagnetic limit. Comparing the condensation energy of the Bardeen-Cooper-Schrieffer (BCS) singlet ground…
Switching between attractive and repulsive Coulomb-interaction-mediated drag in an ambipolar GaAs/AlGaAs bilayer device
B. Zheng, A. F. Croxall, J. Waldie +5
We present measurements of Coulomb drag in an ambipolar GaAs/AlGaAs double quantum well structure that can be configured as both an electron-hole bilayer and a hole-hole bilayer, w…
Effect of parameter mismatch on the synchronization of strongly coupled self sustained oscillators
N. Chakrabarty, A. Jain, Nijil Lal C. K. +2
In this paper we present an experimental setup and an associated mathematical model to study the synchronization of two self sustained strongly coupled mechanical oscillators (metr…
Landau level spin diode in a GaAs two dimensional hole system
O. Klochan, A. R. Hamilton, K. das Gupta +3
We have fabricated and characterized the Landau level spin diode in GaAs two dimensional hole system. We used the hole Landau level spin diode to probe the hyperfine coupling betwe…
Fabrication and characterisation of ambipolar devices on an undoped AlGaAs/GaAs heterostructure
J. C. H. Chen, D. Q. Wang, O. Klochan +7
We have fabricated AlGaAs/GaAs heterostructure devices in which the conduction channel can be populated with either electrons or holes simply by changing the polarity of a gate bia…
Ultra-shallow quantum dots in an undoped GaAs/AlGaAs 2D electron gas
W. Y. Mak, F. Sfigakis, K. Das Gupta +7
We report quantum dots fabricated on very shallow 2-dimensional electron gases, only 30 nm below the surface, in undoped GaAs/AlGaAs heterostructures grown by molecular beam epitax…
Linear non-hysteretic gating of a very high density 2DEG in an undoped metal-semiconductor-metal sandwich structure
K. Das Gupta, A. F. Croxall, W. Y. Mak +5
Modulation doped GaAs-AlGaAs quantum well based structures are usually used to achieve very high mobility 2-dimensional electron (or hole) gases. Usually high mobilities ($>10^{7}{…
Distinguishing impurity concentrations in GaAs and AlGaAs, using very shallow undoped heterostructures
W. Y. Mak, K. Das Gupta, H. E. Beere +3
We demonstrate a method of making a very shallow, gateable, undoped 2-dimensional electron gas. We have developed a method of making very low resistivity contacts to these structur…
On the Zero-Bias Anomaly in Quantum Wires
S. Sarkozy, F. Sfigakis, K. Das Gupta +4
Undoped GaAs/AlGaAs heterostructures have been used to fabricate quantum wires in which the average impurity separation is greater than the device size. We compare the behavior of…
Low Temperature Transport in Undoped Mesoscopic Structures
S. Sarkozy, K. Das Gupta, C. Siegert +6
Using high quality undoped GaAs/AlGaAs heterostructures with optically patterned insulation between two layers of gates, it is possible to investigate very low density mesoscopic r…
Insulator superconductor transition on solid inert gas substrates
K. Das Gupta, Swati S. Soman, G. Sambandamurthy +1
We present observations of the insulator-superconductor transition in ultrathin films of Bi on solid xenon condensed on quartz and on Ge on quartz. The relative permeability $ε_{r}…
Vortices and the mixed state of ultrathin Bi films
G. Sambandamurthy, K. Das Gupta, Swati S. Soman +1
Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These show hysteresis for all films, grown both wit…
Critical currents and vortex-unbinding transitions in quench-condensed ultrathin films of Bismuth and Tin
K. Das Gupta, Swati S. Soman, G. Sambandamurthy +1
We have investigated the I-V characteristics of strongly disordered ultra-thin films of {\it Bi} and {\it Sn} produced by quench-condensation. Our results show that both these syte…
Vortex dynamics and upper critical fields in ultrathin Bi films
G. Sambandamurthy, K. Das Gupta, N. Chandrasekhar
Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin films in a magnetic field are reported. These I-V's show hysteresis for all films, grown…
Effect of granularity on the insulator-superconductor transition in ultrathin Bi films
G. Sambandamurthy, K. Das Gupta, N. Chandrasekhar
We have studied the insulator-superconductor transition (IST) by tuning the thickness in quench-condensed films. The resistive transitions of the superconducting films are smo…
Possible robust insulator-superconductor transition on solid inert gas and other substrates
K. Das Gupta, G. Sambandamurthy, Swati S. Soman +1
We present observations of the insulator-superconductor transition in ultrathin films of Bi on amorphous quartz, quartz coated with Ge, and for the first time, solid xenon condense…