Jainendra K. Jain

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Disorder plays an important role in two dimensions, and is responsible for striking phenomena such as metal-insulator transition and the integral and fractional quantum Hall effects. In this Letter, we investigate the role of disorder in the context of the recently discovered topological insulator, which possesses a pair of helical edge states with opposing(More)
It is demonstrated that an understanding of the 5/2 fractional quantum Hall effect can be achieved within the composite fermion theory without appealing to the Pfaffian wave function. The residual interaction between composite fermions plays a crucial role in establishing incompressibility at this filling factor. This approach has the advantage of being(More)
It is shown, with the help of exact diagonalization studies on systems with up to 16 electrons, in the presence of up to two delta function impurities, that the Pfaffian model is not accurate for the actual quasiholes and quasiparticles of the 5/2 fractional quantum Hall effect. Implications for non-Abelian statistics are discussed.
From a combination of careful and detailed theoretical and experimental studies, we demonstrate that the Boltzmann theory including all scattering mechanisms gives an excellent account, with no adjustable parameters, of high electric field transport in single as well as double-oxide graphene transistors. We further show unambiguously that scattering from(More)
When two-dimensional electrons are subjected to a very strong magnetic field, they are believed to form a triangular crystal. By a direct comparison with the exact wave function, we demonstrate that this crystal is not a simple Hartree-Fock crystal of electrons but an inherently quantum mechanical crystal characterized by a nonperturbative binding of(More)
It has been over 10 years since the discovery of an evendenominator fractional quantum Hall effect ~FQHE! at Landau level ~LL! filling fraction n55/2. In this state the lowest (n50) LL is filled for both up spins and down spins and the effective filling factor of the first-excited (n51) LL is 1/2. In an attempt to explain how this state was able to escape(More)
We report on exact diagonalization studies for fully spin polarized 5/2 fractional quantum Hall effect, incorporating Landau-level mixing through the Bishara-Nayak effective interaction. We find that there is an experimentally accessible region in the phase diagram where the Pfaffian model accurately describes not only the ground state but also the neutral(More)
A microscopic confirmation of the fractional statistics of the quasiparticles in the fractional quantum Hall effect has so far been lacking. We calculate the statistics of the composite-fermion quasiparticles at nu=1/3 and nu=2/5 by evaluating the Berry phase for a closed loop encircling another composite-fermion quasiparticle. A careful consideration of(More)
The interaction between superconductivity and ferromagnetism, which entails incompatible spin order, is one of the problems of fundamental interest in condensed-matter physics. In general, when a ferromagnet is placed in contact with a superconductor, the Cooper pairs from the superconductor are not expected to survive beyond at most a few nanometres into(More)
While an ordinary Fermi sea is perturbatively robust to interactions, the paradigmatic composite-fermion (CF) Fermi sea arises as a nonperturbative consequence of emergent gauge fields in a system where there was no Fermi sea to begin with. A mean-field picture suggests two Fermi seas, of composite fermions made from electrons or holes in the lowest Landau(More)