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 38 for “"Charge Density Wave (CDW)"”.
-
Structure and Motion of Charge Density Waves: An Nmr Study of Niobium-Selenide(3)
The author reports Nb('93) NMR studies of the charge density wave (CDW) conductor, NbSe(,3), using aligned, multicrystalline samples, observing the NMR with and without current flow in the crystals.
-
Quantum Tunneling of Charge-Density Waves in Quasi-One-Dimensional Conductors (Trichalcogenide, Tantalum Trisulfide, Niobium-Triselenide)
The charge-density wave (CDW) dynamics of the linear chain compound orthorhombic TaS(,3) is characterized by extensive measurements of dc conductivity, ac admittance, direct mixing, harmonic mixing, second harmonic generation, and third harmonic generation as functions of dc bias voltage, applied …
-
Confirmation of Mcmillan's Concept of Discommensurations in 2h-Tantalum-Diselenide
… crystal sample of 2H-TaSe(,2) to study the charge density wave (CDW) in this compound and to test a concept put forth by McMillan. We compare the temperature dependence of the NMR lineshape obtained by Couturie from 4.2 K to 130 K with a lineshape theory which encompasses McMillan's theory …
-
Confirmation of McMillan's Concept of Discommensurations in 2H-Tantalum Diselenide
… a single crystal sample of 2H-TaSe2 to study the charge density wave (CDW) in this compound and to test a concept put forth by McMillan. We compare the temperature dependence of the NMR lineshape obtained by Couturie from 4.2 K to 130 K with a lineshape theory which encompasses McMillan's theory …
-
Transport studies and phenomenological model for sliding charge-density waves in quasi-one-dimensional conductors
… examining the dynamics of one-dimensional charge-density wave (CDW) condensates are reported. Results using rf and dc, linear and nonlinear electrical transport techniques have been obtained at temperatures below the CDW transition in the quasi-one-dimensional materials o-TaS$\sb3$, …
-
Charge-Density-Wave Transport in Quasi - One-Dimensional Conductors
… remarkable collective-transport properties of charge-density-wave (CDW) conductors is presented. Measurements of current oscillations observed in response to applied dc voltages and of mode-locking phenomena observed in response to combined ac and dc voltages indicate a nearly complete analogy …
-
X-ray Studies of Lattice Dynamics
… was demonstrated by studying phonon softening in charge density wave (CDW) TiSe2 and antiferrodistortive (AFD) SrTiO3. This thesis work helps to develop analysis of x-ray thermal diffuse scattering as a viable method for studies of lattice dynamics.
-
Spontaneous chiral ordering in titanium diselenide
In this work, we studied the chiral charge density wave (CDW) phase in titanium diselenide (TiSe₂) with the circular photogalvanic effect (CPGE). Mechanically exfoliated bulk TiSe₂ flakes were obtained and implemented into nanoscale devices using standard fabrication techniques. Four samples' …
-
Inelastic Light Scattering Studies of Quantum Phase Transitions in Copper Titanium Diselenium and Multiferroic Terbium Manganese Trioxygen
… the effects of intercalation and pressure on the charge-density-wave (CDW) order in this system. All these parameters---temperature, pressure and Cu-intercalation---suppress the CDW state in TiSe2. Our Raman measurements on CuxTiSe2 show that the x-dependent mode softening exhibits identical …
-
Raman Scattering From the Superconductor Niobium-Diselenide
… 33 K 2H-NbSe(,2) distorts into an incommensurate charge density wave (CDW) state. The Raman spectrum shows amplitude modes of A and E symmetry near 40 cm('-1) induced by the CDW. At 7 K this material becomes superconducting, and at 2 K we observe additional Raman peaks near 20 cm('-1), one each of …
-
Coupled one dimensional electron systems and stripe phases of high temperature superconductors
… chapter one, I consider the problem of the Local Density of States for spin-gapped one-dimensional charge density wave (CDW) states and Mott insulators in the presence of a hard-wall boundary. I calculate the boundary contribution to the single-particle Green function in the low-energy limit using …
-
Emergence of charge density wave domain walls above the superconducting dome in TiSe2
… ordered state, such as antiferromagnetism, charge density wave (CDW), or stripe order. This suggests a fundamental connection between SC and fluctuations in some other order parameter. 1T-TiSe2 is a prototypical CDW material in the transtion-metal dichalcogenide family and was previously …
-
An X-ray study of charge-density-wave pinning and a measurement of the thermal conductivity in blue bronze
Two different aspects of the charge-density-wave (CDW) state were studied in the quasi-onedimensional metal blue bronze (Ko.3oMo03). In the primary experiment reported in this thesis, pinning of the CDW phase by lattice imperfections was examined. Pinning determines most of the dynamics of CDW …
-
The Premartensitic Transitions of Titanium Nickel: Observation of a Charge Density Wave in a Binary Alloy
The appearance of a charge-density wave (CDW) and associated phase transitions has been identified in TiNi(Fe), a binary alloy. Bulk thermal and transport measurements have revealed that the "pre-martensitic instability" is composed of two distinct phase transitions. In TiNi(3.2% Fe), these occur …
-
Exploring strongly interacting gapless states : cuprates, pair density waves, and fluctuating superconductivity
We study the physical property of pair density wave (PDW) and fluctuating PDW, and use it to build an effective theory of the strongly interacting pseudogap phase in cuprate high temperature superconductors. In Chapter 2, we study how Fulde-Ferrell state, the simplest form of PDW, responds to …
-
Synthesis of 1T-Tantalum (IV) Sulfide and observation of charge density wave using scanning tunneling microscopy
… A particular example is the existence of a charge density wave (CDW) in 1T-Tantalum (IV) Sulfide (1T-TaS2). A member of the transition metal dichalcogenide (TMDC) family, 1T-TaS2 exhibit a periodic modulation of electronic charge density. Unlike bulk semiconductor or metals, lattice …
-
Electronic instabilities and the Martensitic transition in A-15 compouns
… on Gorkov's physical model of a Peierls-like charge density wave (CDW) transition involving electronic CDW order parameters coupled to phonon coordinates. Pretransition elastic anomalies, softening of the [llOJ transverse ([110J polarized) phonon, sublattice distortions, variation of …
-
Effects of doping on the electronic properties of niobium triselenide
… on both undoped and doped samples of the Charge Density Wave (CDW) material NbSe3 are reported. The magnetic studies show that both magnetic(V) and nonmagnetic(Ta) impurities may be introduced into NbSe3; a sensitive electron microscopy technique for measuring the impurity concentration is …
-
Investigation of elastic effects of sliding charge-density waves
… softening associated with the sliding of a charge-density wave (CDW), driven by an electric field, is investigated in o-TaS$\sb3$ by use of a vibrating-reed technique. Experiments performed with a dc sliding CDW find the magnitude of the change in Young's modulus, Y, to be proportional to …
-
Time resolved dynamics of charge density waves in solids : an uncorrelated and a correlated case
Charge density wave (CDW) is a periodic charge modulation in a metal, induced by electron-phonon or electron-electron interaction, which breaks the translational symmetry of the underlying electron gas. The charge density wave order is ubiquitous among condensed matter systems, and its equilibrium …
Page 1 of 2