B
Brad Ramshaw
Researcher at Cornell University
Publications - 114
Citations - 4592
Brad Ramshaw is an academic researcher from Cornell University. The author has contributed to research in topics: Superconductivity & Fermi surface. The author has an hindex of 28, co-authored 98 publications receiving 3736 citations. Previous affiliations of Brad Ramshaw include Los Alamos National Laboratory & Canadian Institute for Advanced Research.
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Journal ArticleDOI
Broken rotational symmetry in the pseudogap phase of a high- T c superconductor
Ramzy Daou,Johan Juul Chang,David LeBoeuf,O. Cyr-Choinière,Francis Laliberte,Nicolas Doiron-Leyraud,Brad Ramshaw,Ruixing Liang,Ruixing Liang,D. A. Bonn,D. A. Bonn,Walter Hardy,Walter Hardy,Louis Taillefer,Louis Taillefer +14 more
TL;DR: In this paper, it was shown that the pseudogap phase is an electronic state that strongly breaks four-fold rotational symmetry in YBa(2)Cu(3)O(y) that sets in precisely at T* throughout the doping phase diagram.
Journal ArticleDOI
Electron pockets in the Fermi surface of hole-doped high-Tc superconductors.
David LeBoeuf,Nicolas Doiron-Leyraud,Julien Levallois,Ramzy Daou,J.-B. Bonnemaison,Nigel E. Hussey,Luis Balicas,Brad Ramshaw,Ruixing Liang,Ruixing Liang,D. A. Bonn,D. A. Bonn,Walter Hardy,Walter Hardy,S. Adachi,Cyril Proust,Louis Taillefer,Louis Taillefer +17 more
TL;DR: The observation of a negative Hall resistance in the magnetic-field-induced normal state of YBa2Cu3Oy and Y ba2Cu4O8, which reveals that these pockets are electron-like rather than hole-like, is reported, suggesting that a Fermi surface reconstruction also occurs in those materials, pointing to a generic property of high-transition-temperature (Tc) superconductors.
Journal Article
Electron pockets in the Fermi surface of hole-doped high-$T$c superconductors
David Leboeuf,Nicolas Doiron-Leyraud,Julien Levallois,Ramzy Daou,J.-B. Bonnemaison,Nigel E. Hussey,Luis Balicas,Brad Ramshaw,Ruixing Liang,Doug Bonn,Walter Hardy,Seiji Adachi,Cyril Proust,Louis Taillefer +13 more
Journal ArticleDOI
Direct measurement of the upper critical field in cuprate superconductors
Gael Grissonnanche,O. Cyr-Choinière,Francis Laliberte,S. René de Cotret,A. Juneau-Fecteau,Sophie Dufour-Beauséjour,M.-È. Delage,David LeBoeuf,Johan Juul Chang,Johan Juul Chang,Brad Ramshaw,D. A. Bonn,D. A. Bonn,Walter Hardy,Walter Hardy,Ruixing Liang,Ruixing Liang,Seiji Adachi,Nigel E. Hussey,Nigel E. Hussey,B. Vignolle,Cyril Proust,Mike Sutherland,S. Krämer,J.-H.. Park,David Graf,Nicolas Doiron-Leyraud,Louis Taillefer,Louis Taillefer +28 more
TL;DR: The thermal conductivity can be used to directly detect Hc2 in the cuprates Y Ba2Cu3Oy, YBa2Cu4O8 and Tl2Ba2 CuO6+δ, allowing us to map out Hc1 across the doping phase diagram, revealing that phase competition is a key limiting factor in the superconductivity of cuprates.
Journal ArticleDOI
Lifshitz critical point in the cuprate superconductor YBa2Cu3Oy from high-field Hall effect measurements
David LeBoeuf,Nicolas Doiron-Leyraud,B. Vignolle,Mike Sutherland,Brad Ramshaw,Julien Levallois,Ramzy Daou,Francis Laliberte,O. Cyr-Choinière,Johan Chang,Younjung Jo,Luis Balicas,Ruixing Liang,Ruixing Liang,D. A. Bonn,D. A. Bonn,Walter Hardy,Walter Hardy,Cyril Proust,Cyril Proust,Louis Taillefer,Louis Taillefer +21 more
TL;DR: In this article, the Hall coefficient of cuprate superconductor YBa 2Cu3Oy was measured in magnetic fields up to 60 T for a hole concentration p from 0.078 to 0.152 in the underdoped regime.