Florian Loder
University of Augsburg
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Florian Loder.
Nature Physics | 2008
Florian Loder; Arno P. Kampf; T. Kopp; J. Mannhart; C. W. Schneider; Yu. S. Barash
1 ar X iv :0 70 9. 41 11 v1 [ co nd -m at .s up rco n] 2 6 Se p 20 07 The magnetic flux periodicity of superconducting loops as well as flux quantization itself are a manifestation of macroscopic quantum phenomena with far reaching implications. They provide the key to the understanding of many fundamental properties of superconductors and are the basis for most bulk and device applications of these materials. In superconducting rings the electrical current has been known to periodically respond to a magnetic flux with a periodicity of h/2e. Here, the ratio of Planck’s constant and the elementary charge defines the magnetic flux quantum h/e. The well-known h/2e periodicity is viewed to be a hallmark for electronic pairing in superconductors and is considered evidence for the existence of Cooper pairs. Here we show that in contrast to this long-term belief, rings of many superconductor bear an h/e periodicity. These superconductors include the high-Tc cuprates, Sr2RuO4, the heavy-fermion superconductors, as well as all other unconventional superconductors with nodes in the energy gap functions, and s-wave superconductors with small gaps or states in the gap. As we show, the 50-year-old Bardeen–Cooper–Schrieffer theory of superconductivity implies that for multiply connected paths of such superconductors the ground-state energies and consequently also the supercurrents are generically h/e periodic. The origin of this periodicity is a magnetic-field driven reconstruction of the condensate and a concomitant Doppler-shifted energy spectrum. The robust, flux induced reconstruction of the condensate will be an important aspect to understand the magnetic properties of mesoscopic unconventional superconductors. Currents of electrons moving on multiply connected paths are modulated by an applied magnetic flux with a period of h/e , as predicted by Aharonov and Bohm . In superconducting rings the order parameter responds also periodically to a magnetic flux, as Fritz London recognized when he analyzed the implications of a single-valued superconducting wave function; different condensate states, which differ by integer flux quanta, are related by a gauge transformation. London concluded that the flux periodicity in superconducting rings is h/e . He missed, however, a class of supercurrent carrying wave functions, which were identified years later, and allowed to explain the experimentally observed h/2e flux quantization. Indeed, according to the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity the electronic condensate is formed by Cooper pairs, which carry
Physical Review B | 2008
Florian Loder; Arno P. Kampf; T. Kopp
We analyze the crossover from an
Journal of Physics: Condensed Matter | 2013
Florian Loder; Arno P. Kampf; T. Kopp
hc/e
Physical Review B | 2011
Mark H. Fischer; Florian Loder; Manfred Sigrist
periodicity of the persistent current in flux-threaded clean metallic rings toward an
New Journal of Physics | 2009
Florian Loder; Arno P. Kampf; T. Kopp; J. Mannhart
hc/2e
Physical Review Letters | 2011
Florian Loder; Siegfried Graser; Arno P. Kampf; Thilo Kopp
-flux periodicity of the supercurrent upon entering the superconducting state. On the basis of a model calculation for a one-dimensional ring we identify the underlying mechanism, which balances the
Physical Review B | 2010
Florian Loder; Arno P. Kampf; T. Kopp
hc/e
Journal of the Physical Society of Japan | 2014
Manfred Sigrist; D. F. Agterberg; Mark H. Fischer; Jun Goryo; Florian Loder; Sung-Hyon Rhim; Daisuke Maruyama; Youichi Yanase; Tomohiro Yoshida; Suk Joo Youn
versus the
Scientific Reports | 2015
Florian Loder; Arno P. Kampf; Thilo Kopp
hc/2e
Physical Review Letters | 2012
Wolf Fa; Siegfried Graser; Florian Loder; T. Kopp
periodic components of the current density. When the ring circumference exceeds the coherence length of the superconductor, the flux dependence is strictly