Nonlinear dynamics of high-temperature superconductors

ISBN-13: 9783847374237 / Angielski / Miękka / 196 str.

Francesco Piazza

Opis

After 25 years, the microscopic mechanism of High-Tc superconductivity is still an open problem. In particular, the role of lattice vibrations is not yet clear. Many of the proposed models invoke unusual vibrational properties, such as nonlinearity in the interatomic potentials. In this thesis we present a combined experimental and theoretical study of lattice anharmonicities in cuprates. We first introduce and describe our Extended X-Ray Absorption Spectroscopy (EXAFS) experiments. We then develop a novel data analysis technique, which enables us to measure directly the nonlinearity in the interatomic potentials of the copper-oxide planes, which constitute the basic structural unit of all cuprates. Finally, based on our experimental results, we introduce a simple dynamical model of the copper-oxide layers. We study this model both analytically and numerically, showing the emergence of anharmonic localised excitations known from nonlinear physics as discrete breathers.

O autorze

Francesco Piazza was born in Florence, Italy, the 3rd November 1970. He is an associate professorof condensed matter physics at the university of Orléans, France. He plays piano, draws, explores and learnswith his daughters, cooks, teaches and studies, not necessarily in this order.