ISBN 978-3-8439-0050-8

978-3-8439-0050-8, Reihe Physik

Markus Schmid
Disorder- and Field-Induced Inhomogeneities in Unconventional Superconductors

211 Seiten, Dissertation Universität Augsburg (2010), Softcover, B5

Zusammenfassung / Abstract

Since its discovery one century ago, superconductivity has revealed innumerous fascinating novel properties which have been utilized for many applications in our everyday life. This book is devoted to a better understanding of high-temperature superconductivity and its interplay with antiferromagnetic spin-correlations which are both effectuated by the Coulomb interaction between copper electrons. Based on the atomic structure of the cuprates, a microscopic model is developed which is able to describe a wide range of intriguing phenomena.

Specific attention is paid to inhomogeneities, which are identified as a crucial ingredient to the physics of many high-temperature superconductors. Regardless of their particular nature, dopant disorder, impurities, varying pairing interactions, or magnetic fields evoke generically charge redistributions and, beyond a critical Coulomb repulsion, local magnetic order. In this context the “order by disorder” phenomenon is discussed. It turns out that the impurity- and field-induced magnetization in the superconducting state of the cuprates have a common origin. Strong dopant disorder is identified to induce incommensurate antiferromagnetic order as observed in specific underdoped cuprates by neutron scattering measurements. The book explains how antiphase domain walls determine the different temperature dependence of the magnetic moment in zero- and finite magnetic field. Within this theory coexisting unidirectional pair-, spin-, and charge-density wave orders emerge naturally close to 1/8 hole doping above a critical Coulomb interaction. This work supports the notion that fluctuating stripes are pinned by inhomogeneities to become static.