A gallery for mathematics

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2005.Includes bibliographical references (p. 68).The Gallery for Mathematics seeks to interpret and communicate the character and culture of mathematics through the lens of architectural tectonic. The form and program of the Gallery are driven by three goals for the architectural experience and mathematical journey: [movement], [interaction], and [solitude]. By redesigning the traditional museum experience, the Gallery aims not to simply inform its visitors, but instead to incite their curiosity, producing spaces of inquiry rather than spaces of information. Sited on top of the parking garage for Boston's Museum of Science, the Gallery and its garden also serve to reconnect the Boston and Cambridge park systems on opposite banks of the Charles River, embedding theby Molly S. Forr.M.Arch

Optical spectroscopy on monomeric and polymeric 1:1 fulleride salts

We compare infrared spectra of the C-60(-) monoanion in different solid-state structures with each other as well with that of the neutral molecule. We relate the shift and splitting of the T-u infrared modes to the strength and anisotropy of electron-phonon coupling in those environments

Imaging the impact on cuprate superconductivity of varying the interatomic distances within individual crystal unit cells

Many theoretical models of high-temperature superconductivity focus only on the doping dependence of the CuO2-plane electronic structure. However, such models are manifestly insufficient to explain the strong variations in superconducting critical temperature, Tc, among cuprates that have identical hole density but are crystallographically different outside of the CuO2 plane. A key challenge, therefore, has been to identify a predominant out-of-plane influence controlling the superconductivity, with much attention focusing on the distance dA between the apical oxygen and the planar copper atom. Here we report direct determination of how variations in interatomic distances within individual crystalline unit cells affect the superconducting energy-gap maximum Δ of Bi2Sr2CaCu2O8+δ. In this material, quasiperiodic variations of unit cell geometry occur in the form of a bulk crystalline “supermodulation.” Within each supermodulation period, we find ≈9 ± 1% cosinusoidal variation in local Δ that is anticorrelated with the associated dA variations. Furthermore, we show that phenomenological consistency would exist between these effects and the random Δ variations found near dopant atoms if the primary effect of the interstitial dopant atom is to displace the apical oxygen so as to diminish dA or tilt the CuO5 pyramid. Thus, we reveal a strong, nonrandom out-of-plane effect on cuprate superconductivity at atomic scale