Electronic entanglement via quantum Hall interferometry in analogy to an optical method
Diego Frustaglia and Adan Cabello
We present an interferometric scheme producing orbital entanglement in a quantum Hall system upon electron-hole pair emission via tunneling. The proposed setup is an electronic version of the optical interferometer proposed by Cabello et al. [Phys. Rev. Lett. 102, 040401 (2009)] and is feasible with ... [Phys. Rev. B 80, 201312 (2009)] published Fri Nov 20, 2009.
Terahertz photoresponse of a quantum Hall edge-channel diode
Christian Notthoff, Kevin Rachor, Detlef Heitmann, and Axel Lorke
The terahertz (THz) photoresponse of a two-dimensional electron gas in the quantum Hall regime is investigated. We use a sample structure which is topologically equivalent to a Corbino geometry combined with a cross-gate technique. This quasi-Corbino geometry allows us to directly investigate the TH ... [Phys. Rev. B 80, 205320 (2009)] published Thu Nov 19, 2009.
Effects of repulsive and attractive ionized impurities on the resistivity of semiconductor heterostructures in the quantum Hall regime
A. Raymond, I. Bisotto, Y. M. Meziani, S. Bonifacie, C. Chaubet et al.
We have investigated experimentally and theoretically the effect of repulsive and attractive ionized impurities on the resistivity components (rho and rho) in the quantum Hall effect regime. GaAs/GaAlAs asymmetric modulation-doped quantum wells with additional delta doping (by Si donor atoms or Be a ... [Phys. Rev. B 80, 195316 (2009)] published Wed Nov 18, 2009.
Local density of states of electron-crystal phases in graphene in the quantum Hall regime
O. Poplavskyy, M. O. Goerbig, and C. Morais Smith
We calculate, within a self-consistent Hartree-Fock approximation, the local density of states for different electron crystals in graphene subject to a strong magnetic field. We investigate both the Wigner crystal and bubble crystals with M electrons per lattice site. The total density of states con ... [Phys. Rev. B 80, 195414 (2009)] published Tue Nov 17, 2009.
Three-Dimensional Topological Insulators on the Pyrochlore Lattice
H.-M. Guo and M. Franz
Electrons hopping on the sites of a three-dimensional pyrochlore lattice are shown to form topologically nontrivial insulating phases when the spin-orbit (SO) coupling and lattice distortions are present. Of 16 possible topological classes 9 are realized for various parameters in this model. Specifi ... [Phys. Rev. Lett. 103, 206805 (2009)] published Fri Nov 13, 2009.
Gap opening in the zeroth Landau level of graphene
A. J. M. Giesbers, L. A. Ponomarenko, K. S. Novoselov, A. K. Geim, M. I. Katsnelson et al.
We have measured a strong increase of the low-temperature resistivity rho and a zero-value plateau in the Hall conductivity sigma at the charge neutrality point in graphene subjected to high magnetic fields up to 30 T. We explain our results by a simple model involving a field dependent splitting of ... [Phys. Rev. B 80, 201403 (2009)] published Wed Nov 11, 2009.
Anatomy of Abelian and Non-Abelian Fractional Quantum Hall States
B. Andrei Bernevig and N. Regnault
We deduce a new set of symmetries and relations between the coefficients of the expansion of Abelian and non-Abelian fractional quantum Hall (FQH) states in free (bosonic or fermionic) many-body states. Our rules allow us to build an approximation of a FQH model state with an overlap increasing with ... [Phys. Rev. Lett. 103, 206801 (2009)] published Tue Nov 10, 2009.
Surface States of Topological Insulators: The Dirac Fermion in Curved Two-Dimensional Spaces
Dung-Hai Lee
The surface of a topological insulator is a closed two-dimensional manifold. The surface states are described by the Dirac Hamiltonian in curved two-dimensional spaces. For a slablike sample with a magnetic field perpendicular to its top and bottom surfaces, there are chiral states delocalized on th ... [Phys. Rev. Lett. 103, 196804 (2009)] published Thu Nov 5, 2009.
Fractional Topological Insulators
Michael Levin and Ady Stern
We analyze generalizations of two-dimensional topological insulators which can be realized in interacting, time reversal invariant electron systems. These states, which we call fractional topological insulators, contain excitations with fractional charge and statistics in addition to protected edge ... [Phys. Rev. Lett. 103, 196803 (2009)] published Wed Nov 4, 2009.
Anomalous finite size effects on surface states in the topological insulator BiSe
Jacob Linder, Takehito Yokoyama, and Asle Sudbo
We study how the surface states in the strong topological insulator BiSe are influenced by finite size effects and compare our results with those recently obtained for two-dimensional topological insulator HgTe. We demonstrate two important distinctions: (i) contrary to HgTe, the surface states in B ... [Phys. Rev. B 80, 205401 (2009)] published Mon Nov 2, 2009.
Local density of states in disordered two-dimensional electron gases at high magnetic field
Thierry Champel and Serge Florens
Motivated by high-accuracy scanning tunneling spectroscopy measurements on disordered two-dimensional electron gases in strong magnetic field, we present an expression for the local density of states (LDoS) of electrons moving in a smooth arbitrary potential landscape on the scale of the magnetic le ... [Phys. Rev. B 80, 161311 (2009)] published Wed Oct 28, 2009.
Observation of quantum-Hall effect in gated epitaxial graphene grown on SiC (0001)
T. Shen, J. J. Gu, M. Xu, Y. Q. Wu, M. L. Bolen et al.
Epitaxial graphene films examined were formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k gate stack on the epitaxial graphene was realized by inserting a fully oxidized nanometer thin aluminum film as a seeding layer, followed by an atomic ... [Appl. Phys. Lett. 95, 172105 (2009)] published Wed Oct 28, 2009.
Merging of Dirac points in a two-dimensional crystal
G. Montambaux, F. Piechon, J.-N. Fuchs, and M. O. Goerbig
We study under which general conditions a pair of Dirac points in the electronic spectrum of a two-dimensional crystal may merge into a single one. The merging signals a topological transition between a semimetallic phase and a band insulator. We derive a universal Hamiltonian that describes the phy ... [Phys. Rev. B 80, 153412 (2009)] published Tue Oct 27, 2009.
Spin Hall effect in a system of Dirac fermions in the honeycomb lattice with intrinsic and Rashba spin-orbit interaction
A. Dyrdal, V. K. Dugaev, and J. Barnaś
We consider spin Hall effect in a system of massless Dirac fermions in a graphene lattice. Two types of spin-orbit interaction, pertinent to the graphene lattice, are taken into accountthe intrinsic and Rashba terms. Assuming perfect crystal lattice, we calculate the topological contribution to spin ... [Phys. Rev. B 80, 155444 (2009)] published Fri Oct 23, 2009.
Erratum: Filling-Factor-Dependent Magnetophonon Resonance in Graphene [Phys. Rev. Lett. 99, 087402 (2007)]
M. O. Goerbig, J.-N. Fuchs, K. Kechedzhi, and Vladimir I. Fal'ko
Abstract not available. [Phys. Rev. Lett. 103, 179901 (2009)] published Wed Oct 21, 2009.
Exactly solved model for an electronic Mach-Zehnder interferometer
D. L. Kovrizhin and J. T. Chalker
We study nonequilibrium properties of an electronic Mach-Zehnder interferometer built from integer quantum Hall edge states at filling fraction nu=1. For a model in which electrons interact only when they are inside the interferometer, we calculate exactly the visibility and phase of Aharonov-Bohm f ... [Phys. Rev. B 80, 161306 (2009)] published Mon Oct 19, 2009.
Evaluation of experimental techniques for In-line Ion Implantation Characterization
L. Vignoud, F. Milesi, E. Nolot, A. Danel, and S. Favier
This work presents an as exhaustive as possible review of methods which can be applied for in-line monitoring of implant processes. The dynamic of each technique was evaluated for several typical applications. This review shows that methods which are sensitive to electrically active dopants with the ... [AIP Conf. Proc. 1173, 84 (2009)] published Wed Oct 14, 2009.
Non-Traditional Spectroscopy for Analysis of Semiconductor and Photovoltaic Thin Film Materials
Fuhe Li and Scott Anderson
Characterization of semiconductor thin films has long been determined by a number of traditional surface analysis techniques; Auger, ESCA/XPS, SEM-EDS and SIMS to name only a few. Depth profiles, contamination in the thin film or quantitative stoichiometry are specific application examples that pred ... [AIP Conf. Proc. 1173, 62 (2009)] published Wed Oct 14, 2009.
Metrology for Emerging Materials, Devices, and Structures: The Example of Graphene
Alain C. Diebold
New switches are being designed based on carrier spin, excitons, and other properties. Graphene is considered a strong candidate for many of these applications. New phenomena abound at nanoscale dimensions, and graphene is no exception. Quantum confinement impacts materials properties and measuremen ... [AIP Conf. Proc. 1173, 3 (2009)] published Wed Oct 14, 2009.
Molecular Dynamics Calculation of Thermal Conductivity of Graphene Nanoribbons
Jiuning Hu, Xiulin Ruan, Zhigang Jiang, and Yong P. Chen
We have used classical molecular dynamics based on the Brenner potential to calculate the thermal conductivity of rectangular graphene nanoribbons up to 30 nm long. We have employed the Debye model to make the quantum correction of the classical molecular dynamics temperature. The calculated thermal ... [AIP Conf. Proc. 1173, 135 (2009)] published Wed Oct 14, 2009.
Characterization of Integrated Nano Materials
Amal Chabli, Peter Cherns, Nicolas Chevalier, David Cooper, Dominique Lafond et al.
Depending on the level of the technological developments, the characterization techniques are mature to support them or still require protocol definition and relevance demonstration for the issues addressed. For Beyond CMOS and Extreme CMOS devices, the integration of nano-objects like nanowires and ... [AIP Conf. Proc. 1173, 12 (2009)] published Wed Oct 14, 2009.