TcSUH EventS
Special Seminar
The Synthesis, Properties and Chemistry of Layered Solids
by: Prof. Simon J. Clarke
Date: Friday March 30, 2007
Time: 11:00 am – 12:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
New solid state compounds will be described which are composed of alternating transition metal oxide layers and metal sulfide or selenide layers. These compounds show a wide range of electronic, magnetic and structural features which can often be tuned by making substitutions of the cations or anions in the structures.
The lecture will focus firstly on the crystal structures and electronic and magnetic properties of compounds containing titanium, manganese, cobalt or nickel oxide layers separated by copper sulfide or selenide layers. The second part of the lecture will describe the chemical reactivity of these compounds, in particular the reversible room-temperature lithiation of many of these compounds.
A wide range of investigations will be described including diffraction, magnetometry and NMR studies. The properties will be related to the general chemistry of the elements.
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Special Seminar
Materials Science and Technology at the Naval Research Laboratory
by: Dr. Donald Gubser
Date: Wednesday March 28, 2007
Time: 11:00 am – 12:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
A brief introduction to the Naval Research Laboratory will be given, followed by an overview of materials research topics under investigation at NRL. Topics included will be Superconductivity, Acoustic Transduction Materials, Quantum Spin Electronics, Nanocrystals, 3D Materials Visualization, Fracture Simulations, Materials Integration, and Thoracic Surrogate Materials.
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Special Seminar
{Non-linear Tunnelling Characteristics into the Bulk and BoundStates of {\it p}-wave Superconductors}
by: C. J. Bolech
Date: Friday March 23, 2007
Time: 12:00 pm – 1:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
We reconsidered the problem of point-contact tunnel junctions involving low-dimensional superconductors and introduced a simple scheme for computing the full current-voltage characteristics within the framework of non-equilibrium Keldysh-Schwinger Green functions. We extended the formalism from s-wave to p-wave symmetry and proposeed ways of determining, by looking at the Zeeman response, when the superconducting states correspond to spin-triplet pairing. Next, we directed our attention to the zero-energy bound states at the edges or vortex cores of p-wave superconductors; these are predicted to be Majorana fermions. We introduced a model Hamiltonian that describes the tunnelling processes when electrons are injected into such states and we found exact analytic expressions for the tunnelling current and noise. We identified experimental signatures that would confirm the Majorana nature of the bound states.
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Seminar
Merging Form and Function: Insights into Electronically and Magnetically Active Ceramics
by: Dr. Peter Kahlifah
Date: Thursday February 22, 2007
Time: 11:00 am – 12:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
The power of periodic solids is their hybridization of vast arrays of atomic orbitals. This enables strong magnetism, excellent electronic conduction, and a host of intriguing collective phenomena which are generally absent in molecular compounds. The oxides of ruthenium are some of the most interesting transition metal oxides, as they can be very conductive (due to their extended 4d orbitals) while retaining strong magnetic interactions (which are rare outside of the 3d oxides). I will talk about the wide variety of properties observed for the ruthenates I have synthesized and studied, including geometric frustration, orbital ordering, and quantum (T=0) phase transitions. Some properties can be simply explained by a close look at crystal structures, while others need a detailed calculation of their electronic structures, and a few are pushing the envelope of the modern understanding of crystalline solids. I will discuss how a detailed understanding of and control over the energy levels of solids can offer promising solutions to the global need for clean energy.
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Seminar
Structural Studies of Functional Framework Materials
by: Dr. Karena W. Chapman
Date: Monday February 19, 2007
Time: 11:00 am – 12:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
The evolving demands of our modern society fuel a perpetual drive to develop innovative materials for advanced technological and industrial applications. Pivotal to the rational design of next generation materials optimized for real world applications, is the fundamental understanding of the key structural features underlying functional behavior. Here we present recent applications of advanced scattering methods to the development of two novel material functionalities in cyanide-bridged molecular frameworks: negative thermal expansion behavior and reversible hydrogen storage.
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