Abstract
We explore field and temperature scaling of magnetoresistance in underdoped (, ) and optimally doped () samples of the high-temperature superconductor . In all cases, the magnetoresistance is linear at high fields. We demonstrate that the data can be explained by an orbital model in the presence of strongly anisotropic quasiparticle spectra and scattering time due to antiferromagnetism. In optimally doped samples, the magnetoresistance is controlled by the properties of small regions of the Fermi surface called “hot spots,” where antiferromagnetic excitations induce a large quasiparticle scattering rate. The anisotropic scattering rate results in hyperbolic magnetoresistance scaling, which competes with the more conventional Kohler scaling. We argue that these results constitute a coherent picture of magnetotransport in , which links the origin of -linear resistivity to antiferromagnetic hot spots. Implications for the -linear resistivity at zero field are discussed.
- Received 2 July 2020
- Revised 19 October 2020
- Accepted 23 October 2020
DOI:https://doi.org/10.1103/PhysRevX.10.041062
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
High-temperature superconductors exhibit remarkable behavior even in their nonsuperconducting phases. For example, the resistivity varies linearly with temperature and with applied magnetic field, in contrast to the quadratic variation expected in typical metals. It is thought that an understanding of high-temperature superconductivity first requires an understanding of these unusual phenomena in the nonsuperconducting state. In our study, we use a combination of experimental data and theoretical modeling of an iron-based superconductor to show that the momenta of charge carriers rapidly dissipate because of coupling to fluctuations of a nearby magnetic field, thus giving rise to the unconventional variation of electrical resistance.
In our experiments, we measure the resistivity as a function of temperature and magnetic field of the iron-based superconductor with various levels of phosphorus. We then use a realistic theoretical model to capture the resistivity data as a function of temperature, magnetic field, phosphorus-doping level, and systematic defects induced by ion bombardment.
An important implication of this work is that measurements of resistivity in a magnetic field can be used to characterize the properties of magnetic fluctuations, an important ingredient for the development of superconductivity in high-temperature superconducting materials.
