The electrical conductivity of InN, group III-V semiconductor, is measured by four point measurement at low temperatures and high magnetic fields. From Resistance Vs temperature measurements (done in the absence of magnetic field) there is a transition from semiconducting state to superconducting state at 2.5K. This superconducting state disappears when the measurements are repeated but at a magnetic field of 0.1 Tesla. Mover the Hall voltage is not proportional to the magnetic field.

Diss.--Katholieke Universiteit Nijmegen. / Contient le catalogue : the Holbeck library. Bibliogr. p. 339-352.

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Sheila Ortiz-Taylor, Florida State University, College of Arts and Sciences, Dept. of English. Title and description from dissertation home page (viewed June 18, 2004).

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Physics and Astronomy." Includes bibliographical references (p. 65-68).

Thesis (M. Sc.)--University of Hong Kong, 1968. / Mimeographed.

Thesis (M. Sc.)--University of Hong Kong, 1970. / Mimeographed.

The main goal of this project was to write a review about different quantum Hall effects. This review focuses on the integer and relativistic quantum Hall effect in graphene. The quantum Hall effect is a newly discovered phenomena that was experimentally observed in 1980 and relativistic quantum Hall effect in graphene was observed in 2005. This project takes a theoretical approach to describe the quantum Hall effects and graphene itself. Experiments has shown that for very strong magnetic fields applied to 2D systems, the Hall resistance becomes quantized, RH=h/ne2 and only depends on the charge of the electron and Planck's constant, two fundamental constants of nature. This sets a new standard on how to define resistance, and gives a good tool for precise measurements of the fine structure constant.

In this thesis we investigate the electronic band structures and the correlations in chirally (ABC) stacked N-layer graphene with N ≥ 2. We use ab initio density-functional theory and k · p theory to fit the parameters of a p-band tightbinding model. External potential differences between top and bottom layers are strongly screened by charge transfer but still open an energy gap at overall neutrality. Perpendicular magnetic field drives the system into the quantum Hall region with 4N-fold zero energy Landau levels. We predict that Coulomb interactions spontaneously break the SU(4N) symmetry and drive quantum Hall effects at all integer fillings n from −2N to 2N with exotic spin and pseudospin polarizations. Based on mean-field theory and perturbative renormalization group analysis, we predict that the ground state of bilayer graphene spontaneously breaks inversion symmetry for arbitrarily weak electron-electron interactions and conclude that this instability is not suppressed by quantum fluctuations but that, because of trigonal warping, it may occur only in high quality suspended bilayers. Remarkably flat conduction and valence bands that touch at charge neutrality point and Bloch states with large pseudospin chirality combine to make the bilayer graphene gapless band state strongly susceptible to a family of broken symmetry states in which each spinvalley flavor spontaneously transfers charge between layers. We explain how these states are distinguished by their charge, spin, and valley Hall conductivities, by their orbital magnetizations, and by their edge state properties. We further analyze how these competing states are influenced by Zeeman fields that couple to spin and by interlayer electric fields that couple to layer pseudospin, and comment on the possibility of using response and edge state signatures to identify the character of the bilayer ground state experimentally. We demonstrate that similar insulating broken symmetry states and spontaneous topological orders also occur in bilayer’s thicker cousins, chirally stacked multilayer graphene systems. / text

Heterogeneous ferromagnetic-superconducting systems such as a regular array of ferromagnetic nano dots deposited on the top of a superconducting thin film have attracted many research teams both experimental and theoretical. The interest in these systems does not only stem from being good candidates for technological applications, but also because they represent a new class of physical systems where two competing order parameters can coexist. This work focuses on the theoretica laspects of these systems by studying the static and dynamics of few model systems. In the first part, the static properties of a superconducting thin film interacting with a ferromagnetic texture are considered within the London approximation. In particular, the ferromagnetic textures considered here are a circular dot of submicrometer size with in-plane magnetization, an elliptical dot magnetized in the direction perpendicular to the superconductor, and a ferromagnetic dot magnetized in the direction normal to the superconducting film and containing non magnetic cavities. I also consider the interaction of vortices in the superconductor with a ferromagnetic columnar defect which penetrates the supercondcting film. In each case the vector potential and magnetic field of the ferromagnet in the presence of the superconductor are calculated. Afterward the presence of vortices in the superconductor is assumed and the energy of vortex-texture system is found. The pinning potential and force supplied by the texture are then derived from the energy of interaction between the ferromagnet and superconductor. I show that if the magnetization of the ferromagnet exceeds a critical value then vortices are spontaneously created in the ground state of the system. Such spontaneous creation of vortices is possible mostly in a close vicinity of the superconducting transition temperature Ts. For every case, the threshold value of the magnetization at which vortices start to be spontaneously created in the SC is calculated as a function of the parameters of the texture geometry. The phase diagrams for transitions from vortexless regime to regimes with one or more vortices are determined for all cases. In the second problem, the transport properties of a ferromagnetic superconducting bilayer with alternating magnetization and vortex density are studied within a phenomenological model. I show that pinning forces do not appear for continuous distribution of vortices, so a discrete model for the bilayer system is constructed. Afterward, I calculate the pinning forces acting on vortices and antivortices resulting from highly inhomogeneous distribution of flux lines and prove that this system has strong transport anisotropy. In the absence of random pinning, the system displays a finite resistance for the current in the direction perpendicular to the domains while its resistance vanishes for the parallel current. The transport anisotropy strongly depends on temperature. I study this dependence and show that the ratio of parallel to perpendicular critical current is largest close to the superconducting transition temperature Ts and the vortex disappearance temperature Tv while it has a minimum in between them.

See also: Acoustics in architectural design : an annotated bibliography on architectural acoustics. / When Redpath Hall, originally designed and built as a library reading room, was converted into a multi-purpose auditorium, it soon became evident that the Hall was deficient, in several respects, in its new role. The multipurpose hall is, by design, a compromise, designed to provide reasonable hearing conditions for a multiplicity of instrumental and vocal performances, without favoring or overly impairing any particular type of performance. Redpath Hall possesses a relatively long reverberation time, decidedly beneficial for the appreciation of some musical performances, such as organ recitals, chamber music, choral performances, string quartet, etc., but at the same time, noticeably detrimental for other performances; those instruments that excell with a long reverberation time, tend to mask other instruments, resulting in a definite orchestral imbalance, particularly noticeable in remote seats; quick passages of solo instruments are blurred; the spoken word is not intelligible. [...]