A5008941436- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Quantum and electron transport phenomena
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Topological Materials and Phenomena
- Surface and Thin Film Phenomena
- Electronic and Structural Properties of Oxides
- Rare-earth and actinide compounds
- Magnetism in coordination complexes
- Iron-based superconductors research
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Crystal Structures and Properties
- Multiferroics and related materials
- Nuclear physics research studies
- Superconductivity in MgB2 and Alloys
- Superconducting Materials and Applications
Johns Hopkins University
2019-2022
Center for Excellence in Basic Sciences
2016-2019
University of Mumbai
2016-2019
The thermal conductivity of CoNb${}_{2}$O${}_{6}$ is suppressed around its quantum critical point whereas the specific heat enhanced, highlighting role frustration in determining magnetic excitations.
NiNb$_{2}$O$_{6}$ is an almost ideal realization of a 1D spin-1 ferromagnetic Heisenberg chain compound with weak unidirectional anisotropy. Using time-domain THz spectroscopy, we measure the low-energy electrodynamic response as function temperature and external magnetic field. At low temperatures, find magnon-like spin-excitation, which corresponds to lowest energy excitation at $q\sim0$. higher unexpectedly observe temperature-dependent renormalization spin-excitation energy, has strong...
Epitaxial bilayer films of Bi(110) and Ni host a time-reversal symmetry (TRS) breaking superconducting order with an unexpectedly high transition temperature $T_c = 4.1$ K. Using time-domain THz spectroscopy, we measure the low energy electrodynamic response Bi/Ni thin film from $0.2$ to $2$ as function magnetic field. We analyze data in context BCS-like superconductor finite normal-state scattering rate. In zero field, all states become fully gapped, providing important constraints into...
Two-dimensional electron gasses (2DEG) in InAs quantum wells proximitized by aluminum are promising platforms for topological qubits based on Majorana zero modes. However, there still substantial uncertainties associated with the nature of electronic states at interfaces these systems. It is challenging to probe properties hybridized as they buried under a relatively thick layer. In this work, we have investigated range InAs/In$ _{1-\text{x}} $Ga$ _\text{x} $As heterostructures Al overlayers...
We present a thorough experimental study of the three-dimensional hyperhoneycomb Kitaev magnet $\beta$-Li$_2$IrO$_3$, using combination inelastic neutron scattering (INS), time-domain THz spectroscopy, and heat capacity measurements. The main results include massive low-temperature reorganization INS spectral weight that evolves into broad peak centered around 12 meV, distinctive in data at 2.8(1) meV. A detailed comparison to powder-averaged spin-wave theory calculations reveals positions...
The recent observation of cyclotron resonance in optimally-doped La$_{2-x}$Sr$_x$CuO$_4$ using time-domain THz spectroscopy high magnetic field has given new possibilities for the study cuprate superconductors. One can measure mass more disordered cuprates possesing short scattering times therefore expanding to materials and dopings which quantum oscillations have not been observed. Here we present measurement carrier hole doped across a range spanning slightly underdoped ($x=0.13$) highly...
We show that under an ac magnetic field excitation the vortex lattice in a superconductor with periodic array of holes can undergo transition from Mott-like state where each is localized hole, to metal-like vortices get delocalized. The dynamics studied through shielding response which measured using low-frequency two-coil mutual inductance technique on disordered superconducting NbN film having holes. observe strongly dependent amplitude excitation. At low varies smoothly amplitude,...
The structure of decoupled positive-parity and semidecoupled negative-parity bands up to high spin in $^{197,199}\mathrm{Hg}$ has been studied using multinucleon transfer reactions with the Gammasphere array. A band $^{199}\mathrm{Hg}$ ${(\ensuremath{\nu}{i}_{13/2})}^{3}$ configuration that deexcites levels sequences is newly established. both isotopes are extended higher spin. Rotation-aligned angular momenta crossing frequencies determined from experiment fair agreement those cranking...
Thin films of $\ensuremath{\beta}$-tungsten host superconductivity in the presence strong spin-orbit coupling. This nonequilibrium crystalline phase tungsten has attracted considerable attention recent years due to its giant spin Hall effect and potential promise exotic superconductivity. However, more than 60 after discovery, this material is still not well understood. Using time-domain terahertz spectroscopy, we measure frequency response complex optical conductivity thin film with a...
Inelastic neutron scattering (INS) measurements of powder D$_3(^{7}$Li)($^{193}$Ir)$_2$O$_6$ reveal low energy magnetic excitations with a cross section that is broad in $|Q|$ and consistent Kitaev spin-liquid (KSL) state. The nature the excitation spectrum demonstrated by longitudinally polarized studies. total moment 1.7(2)$\mu_B$/Ir inferred from effective susceptibility data expectations for $J_{\rm eff}=1/2$ single ion rise dynamic correlation function ${\cal S}(Q,\omega)$...
We present a critical analysis of an alternative technique point contact Andreev reflection (PCAR) spectroscopy used to extract energy resolved information superconductors which is based on making 'soft-contacts' between and indium. This not sensitive mechanical vibrations hence can be in cryogen free platform increasing its accessibility users having no access cryogenic liquids. Through our experiments large number superconducting films we show that the PCAR spectra below T c In...
Point contact Andreev Reflection (PCAR) spectroscopy is a powerful tool to study superconductors, in particular the superconducting energy gap and its symmetry. We report on use of "soft point technique" which has been integrated with cryogen free platform where vibrations does not disturb stability giving noise PCAR spectra. further show for large area, high transparency junctions between normal metals an additional peak observed spectra at zero bias referred as conductance (ZBC) anomaly....