Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 20 for “"Weyl Semimetal"”.
-
COMPOSITION AND PRESSURE DEPENDENT STUDY ON WEYL SEMIMETAL Mo1-xWxTe2
… work, the doping and pressure effects on the Weyl semimetal Mo1−xWxTe2 have been investigated. A series of single crystals of Mo1−xWxTe2 for x = 0, 0.10, 0.30, 0.40, 0.50, 0.70, 0.75, 0.90, and 1 were synthesized using the self-flux method (for parent compounds MoTe2 and WTe2) and the chemical …
-
Scanning tunneling microscopy studies of a tunable topological insulator and magnetic Weyl semimetal
… system Ge(Bix,Sb1-x)2Te4 and the magnetic Weyl semimetal Co3Sn2S2 were studied. In Ge(Bix,Sb1-x)2Te4, increasing Sb substitution effectively electron dopes the sample and moves the Dirac point from 300 meV below the Fermi energy to energies above the Fermi energy while remaining …
-
Magnetic Weyl Semimetals for Spintronic Applications
Magnetic Weyl semimetals are a category of topological materials that hold promise for spintronic applications due to their unconventional transport properties, which arise from both bulk and surface topological states, as well as the rich interplay between band topology and magnetism. Among the …
-
Exploring linear and nonlinear electromagnetic responses in topological materials
… are covered in this thesis are the conventional Weyl semimetal, the Kramers Weyl semimetal, and the moiré Chern insulator. We begin this research topic by understanding how charge-density waves impact electric field-induced transport in the topological system: the Weyl semimetal.Research over the …
-
Electronic properties of topological semimetal candidates ACd$_2$Pn$_2$ (A = Eu, Sr; Pn = As, Sb)
Weyl semimetals have attracted significant attention due to their intriguing electronic properties arising from the presence of Weyl points. Among them, ideal magnetic Weyl semimetals, characterized by a single pair of Weyl points close to the Fermi level, have long been sought for exploring the …
-
Optical and electrical properties of narrow gap germanium-tin alloys with high tin contents for middle and far infrared applications
… and expand on the current predictive models. ☐ Weyl semimetals are a new topological state of matter in semimetals without either spatial inversion or time-reversal symmetry, are characterized by their zero-energy, direct bandgaps, and exhibit novel electronic properties. An active area of …
-
Topological Phases in Perovskite Iridates with Strong Spin-Orbit Coupling
… different symmetries are broken, including a Weyl and nodal-line semimetal. Secondly, we provide a generic condition to identify a novel three-dimensional topological semi-metallic phase in materials with strong spin-orbit coupling. Such a semi-metallic phase is featured by bulk gapless …
-
Nonreciprocal and Exotic Radiative Transfer in Type-I Magnetic Weyl Semimetals
… recently discovered family of quantum materials—Weyl semimetals—can possess intrinsic nonreciprocity due to the Berry curvature, an internal, pseudo-magnetic field. In this dissertation, we explore thermal radiation from type-I magnetic Weyl semimetals in planar configurations in the far- and …
-
An Investigation into Topological Crystals and Flat Band Systems
… include the topological insulator Cu₂Ti, the Weyl semimetal VMg₂O₄, and the nodal semimetal PtSeTe. The flat band systems investigated all incorporate the 2-dimensional Kagome lattice in their 3-dimensional structures, and include the materials Zr₂Fe₃(Si,Ge) and Fe₆Ge₆Zr. Synthesis campaigns …
-
Patterns of electro-magnetic response in topological semi-metals
Topological semimetals are gapless states of matter which have robust and unique electromagnetic responses and surface states. In this thesis, we consider semimetals which have point like Fermi surfaces in various spatial dimensions $D=1,2,3$ which naturally occur in the transition between $n$th …
-
Tailoring charge to spin conversion in novel materials for efficient spintronics
… chemical order in the newly discovered magnetic Weyl semimetal (MWSM), Co₂MnGa, we can control the spin-charge conversion. Tailoring this interconversion efficiency will lead to energy-efficient and highly tunable memory and computing devices.
-
DEGENERATE SECOND ORDER NONLINEAR OPTICAL SPECTROSCOPY OF CHIRAL WEYL SEMIMETALS
… the measurement of topological properties of the Weyl semimetals. The first portion of this thesis describes technical developments of the nonlinear optical spectroscopic probes rotational anisotropy second harmonic generation (RA-SHG) and transient grating. In our work on SHG, we describe a …
-
Navigating the Intermetallic Landscape: From Quasicrystal Approximants to High Pressure Crystal Chemistry
… as pressure-induced superconductivity in the Weyl semimetal (Mo0.5W0.5)Te2. These results support the formation of complex crystal structures enabled by Au, pressure-stabilized platinide phases and the presence of superconductivity in (Mo0.5W0.5)Te2 at high-pressure. Highlighting the use of …
-
Harnessing Magnetic Switching and Dynamics Using Electron and Magnon Spin Currents
… spin-orbit torque switching of a ferromagnetic Weyl semimetal, where the topological properties are manipulated by the magnetic switching. Besides, spin wave can also transmit spin via magnon spin current. In the third work, we used magnetic domain walls to manipulate the phase and magnitude of …
-
Development of Broadband Time-Resolved Spectroscopy and Investigation of the Dynamics of Photoexcited Carriers and Lattice Excitations in Chiral Weyl Semimetals
… carriers and topological phonons in chiral Weyl semimetals. In the first portion of this thesis, we describe a novel, optical pump supercontinuum probe technique based upon a nonlinear photonic crystal fiber and a digital micro-mirror device enabling the use of single element detector and …
-
Scanning tunneling microscopy and spectroscopy study of phase transitions and topology in layered transition metal dichalcogenides
… charge density wave (CDW), Mott physics, Weyl fermions and others. This class of materials has been known for decades but it received a renovated interest after the discovery of graphene and the development of tools to isolate single layers from layered materials. TMDs are suitable for …
-
Scanning tunneling microscopy and spectroscopy study of layered transition metal chalcogenide thin films tuned by thickness, structural phase, and heterostructure
… phase of quantum matter, while bulk WTe2 is a Weyl semimetal. Moreover, the electronic and magnetic properties of thin films are able to be tuned by various methods, including chemically doping, electrically gating, varying the structural phase, changing the sample thickness, constructing …
-
Higher-order topological phases with crystalline symmetries
… states. We then study the gapless topological semimetals having crystalline symmetries. We identify a new type of Weyl semimetals, the higher-order Weyl semimetal (HOWSM), which hosts arc-like gapless states at both the surfaces and the hinges in a bounded 3D lattice. A 2nd-order Weyl node can …
-
Topological insulators and semimetals in the presence of interactions
Topological insulators and semimetals possess the exotic gapless excitations that are governed by relativistic quantum mechanics. Due to the growing interests in these phases, the number of the materials predicted and shown to have the topological characters are continuously increasing. …
-
Manipulation and analysis of topological properties in hybrid Dirac materials [Manipolazione ed analisi delle proprietà topologiche dei materiali di Dirac]
… vengono studiati due tipi di sistemi: i semimetalli a linea nodale ingegnerizzati tramite campi Floquet e le eterostrutture superconduttive a base di grafene. Nella prima parte della tesi, studiamo gli stati di interfaccia che emergono quando due regioni di un semimetallo a linea nodale …