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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Condensed Matter From Gauge/Gravity Duality, Jason Edward Therrien
Condensed Matter From Gauge/Gravity Duality, Jason Edward Therrien
Doctoral Dissertations
Currently strongly coupled systems present the greatest challenge to theoretical physics. For years conventional methods of approach have failed to describe these systems analytically. In recent years it has been shown that there is a duality between weakly coupled and strongly coupled systems, the Gauge Theory/Gravity Duality. In this dissertation I will discuss how the AdS/CFT is used to describe strongly coupled condensed matter systems as well as present the work done by the author and collaborators.
Magnetic Excitations In The Iron Based Superconductors, Leland Weldon Harriger
Magnetic Excitations In The Iron Based Superconductors, Leland Weldon Harriger
Doctoral Dissertations
Presented within are neutron scattering studies detailing the spin dynamics of BaNi$_{x}$Fe$_{2-x}$As$_{2}$ for x = 0 (parent), 0.04 (underdoped), and 0.1 (optimal) dopings, and FeSe$_{x}$Te$_{1-x}$ for x = 0 (parent), 0.3 (underdoped), and 0.4 (optimal) dopings. These recently discovered Fe-based superconducting compounds are strikingly similar, in many respects, to the cuprate class of unconventional superconductors and share qualitatively similar phase diagrams consisting of a long range ordered magnetic ground state in the parents which, upon doping, is supplanted in favor of superconductivity. The dopings discussed herein allow us to tune through the phase diagram, beginning with long range ordered parents …
Iron Pnictides: Superconductivity In Multi-Orbital Systems, Andrew David Nicholson
Iron Pnictides: Superconductivity In Multi-Orbital Systems, Andrew David Nicholson
Doctoral Dissertations
This work focuses on the development and implementation of microscopic models as well as their numerical and analytical study to elucidate the properties of the iron pnictides. There are many first principle and phenomenological studies of these materials, but there is a need for unbiased numerical calculations following an approach similar to the one used in the study of the Hubbard and t-J models for the cuprates.
First a two orbital model for the pnictides, focusing on two hybridized Fe-d orbitals (dxz and dyz) is formulated, including hoppings between nearest and next nearest neighbors as well as on site Coulomb …
Superconducting Nafe1-Xcoxas: Crystal Growth, Resistivity, And Susceptibility Measurements, Tucker Netherton
Superconducting Nafe1-Xcoxas: Crystal Growth, Resistivity, And Susceptibility Measurements, Tucker Netherton
Chancellor’s Honors Program Projects
No abstract provided.
Majorana Modes In Time-Reversal Invariant S -Wave Topological Superconductors, Shusa Deng, Lorenza Viola, Gerardo Ortiz
Majorana Modes In Time-Reversal Invariant S -Wave Topological Superconductors, Shusa Deng, Lorenza Viola, Gerardo Ortiz
Dartmouth Scholarship
We present a time-reversal invariant s-wave superconductor supporting Majorana edge modes. The multiband character of the model together with spin-orbit coupling are key to realizing such a topological superconductor. We characterize the topological phase diagram by using a partial Chern number sum, and show that the latter is physically related to the parity of the fermion number of the time-reversal invariant modes. By taking the self-consistency constraint on the s-wave pairing gap into account, we also establish the possibility of a direct topological superconductor-to-topological insulator quantum phase transition.
Magnetic Properties Of Nb/Ni Superconducting / Ferromagnetic Multilayers, Sergiy A. Kryukov
Magnetic Properties Of Nb/Ni Superconducting / Ferromagnetic Multilayers, Sergiy A. Kryukov
Theses and Dissertations--Physics and Astronomy
Magnetic properties of Nb/Ni superconducting (SC) / ferromagnetic (FM) multilayers exhibit interesting properties near and below SC transition. A complex Field (H) – Temperature (T) phase boundary is observed in perpendicular and parallel orientation of ML with respect to DC field. We address the critical need to develop methods to make reliable magnetic measurements on SC thin films and ML, in spite of their extreme shape anisotropy and the strong diamagnetic response of the SC state.
Abrupt, highly reproducible “switching” of the SC state magnetization near the normal-state FM coercive fields has been observed in Nb/Ni ML. The SC penetration …