Related papers: A two-coil mutual inductance technique to study ma…
The perpendicular critical fields of a superconducting film have been strongly enhanced by using a nanoengineered lattice of magnetic dots (dipoles) on top of the film. Magnetic-field-induced superconductivity is observed in these hybrid…
We develop a consistent treatment of disorder effects in strong coupling superconductors. We use two different approaches, starting either from above or below the transition temperature, and show their equivalence. The normal state approach…
We investigate the magnetic field evolution of the superconducting state in a strongly disordered NbN thin film which exhibits a magnetic field tuned superconductor to insulator-like transition, employing low temperature scanning tunneling…
We study the crossover in a zero temperature superconducting nanofilm from a single to a double superconducting slab induced by a tunable insulating potential barrier in the middle. The single phase superconducting ground state of this…
Motivated by recent observations of chiral-induced magnetization and spin-selective transport we studied the effect of chiral molecules on conventional BCS superconductors. By applying scanning tunneling spectroscopy, we demonstrate that…
Recent measurements of the magnetoresistance (MR) of amorphous superconducting thin films in tilted magnetic fields have displayed several surprising experimental details, in particular a strong dependence of the MR on field angle at low…
Thin films of the high-temperature superconductor HgBa$_2$CaCu$_2$O$_{6+\delta}$ have been prepared on SrTiO$_3$ substrates by pulsed-laser deposition of precursor films and subsequent annealing in mercury-vapor atmosphere. The…
Understanding the origin of superconductivity in correlated two-dimensional materials is a key step in leveraging material engineering techniques for next-generation nanoscale devices. The recent demonstration of superconductivity in Bernal…
The magnetically driven superconductor-insulator transition in amorphous thin films (e.g., InO, Ta) exhibits several mysterious phenomena, such as a putative metallic phase and a huge magnetoresistance peak. Unfortunately, several…
Using a microscopic approach, we revisit the problem of superconducting critical temperature change in the presence of twin boundaries. We show that both critical temperature enhancement and suppression can come purely from geometric…
Superconductivity has been induced in insulating ultra-thin films of amorphous bismuth using the electric field effect. The screening of electron-electron interaction was found to increase with electron concentration in a manner correlated…
Thin films of alkali metals when sandwiched at both surfaces by thin metal films loose their conductance. The superconducting proximity effect is used to investigate the change in the alkali film. On the length scale of the film thickness…
Kinetic inductance in thin film superconductors has been used as the basis for low-temperature, low-noise photon detectors. In particular thin films such as NbTiN, TiN, NbN, the kinetic inductance effect is strongly non-linear in the…
We present tunneling spectroscopy and transport measurements on disordered indium oxide films that reveal the existence of a superconducting gap in an insulating state. Two films on both sides of the disorder induced superconductor to…
We have measured the Raman spectra of polycrystalline MgB$_{2}$ from 25 {\cm} to 1200 {\cm}. When the temperature was decreased below the superconducting transition temperature $T_c$, we observed a superconductivity-induced redistribution…
The BCS theory has achieved widespread success in describing conventional superconductivity. However, when the length scale reaches the atomic limit, the reduced dimensionality may lead to the quantum breakdown resulting in unpredictable…
The origin of superconductivity in magic-angle twisted bilayer graphene has been a subject of intense debate. While some experimental evidence indicated an unconventional pairing mechanism, efforts to tune the critical temperature by…
The work reported in my doctoral thesis is an experimental study of vortex dynamics and phase transitions in thin films of type II superconductors using scanning tunneling spectroscopy, low frequency ac susceptibility measurements and…
Recent scanning tunnelling microscopy experiments in NbN thin disordered superconducting films found an emergent inhomogeneity at the scale of tens of nanometers. This inhomogeneity is mirrored by an apparent dimensional crossover in the…
We analyze the influence of the surface passivation produced by oxides on the superconducting properties of $\gamma$-Mo$_2$N ultra-thin films. The superconducting critical temperature of thin films grown directly on Si (100) with those…