Paul Goddard
Los Alamos National Laboratory
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Featured researches published by Paul Goddard.
Physical Review B | 2010
Suchitra E. Sebastian; N. Harrison; Paul Goddard; M. M. Altarawneh; C. H. Mielke; Ruixing Liang; D. A. Bonn; W. N. Hardy; O. K. Andersen; G. G. Lonzarich
We report quantum oscillations in the underdoped high Tc YBCO over a wide range in magnetic field 28<B<85 T corresponding to ~12 oscillations, enabling the Fermi surface topology to be mapped to high resolution. As earlier reported by Sebastian et al., we find a Fermi surface comprising multiple pockets, as revealed by the additional distinct quantum oscillation frequencies and harmonics reported in this work. We find the originally reported broad low frequency Fourier peak at 535 T to be clearly resolved into three separate peaks at 460 T, 532 T and 602 T. Our increased resolution and angle-resolved measurements identify these frequencies to originate from two similarly sized pockets with greatly contrasting degrees of interlayer corrugation. The spectrally dominant frequency originates from a pocket (alpha) that is almost ideally two-dimensional in form. In contrast, the newly resolved weaker adjacent spectral features originate from a deeply corrugated pocket (gamma). On comparison with band structure, the d-wave symmetry of the interlayer dispersion locates the minimally corrugated alpha pocket at the nodal point where holes are located in a translational symmetry-broken scenario, and the significantly corrugated gamma pocket at the antinodal point in the Brillouin zone, where electrons are located in a translational symmetry-broken scenario. Translational symmetry breaking by an SDW is suggested from the strong suppression of Zeeman splitting for the spectrally dominant pocket, additional evidence for which is provided from the harmonics we resolve in the present experiments. Given the similarity in alpha and gamma pocket sizes, their opposite carrier type and the previous report of a diverging effective mass, we discuss the possibility of a secondary Fermi surface instability at low dopings of the excitonic insulator type, associated with the metal-insulator QCP.
Physical Review B | 2004
Paul Goddard; Stephen J. Blundell; John Singleton; Ross D. McDonald; Arzhang Ardavan; Alessandro Narduzzo; John A. Schlueter; Aravinda M. Kini; T. Sasaki
The angle-dependences of the magnetoresistance of two different isotopic substitutions (deuterated and undeuterated) of the layered organic superconductor kappa-(ET)2Cu(NCS)2 are presented. The angle dependent magnetoresistance oscillations (AMRO) arising from the quasi-one-dimensional (Q1D) and quasi-two-dimensional (Q2D) Fermi surfaces in this material are often confused. By using the Boltzman transport equation extensive simulations of the AMRO are made that reveal the subtle differences between the different species of oscillation. No significant differences are observed in the electronic parameters derived from quantum oscillations and AMRO for the two isotopic substitutions. The interlayer transfer integrals are determined for both isotopic substitutions and a slight difference is observed which may account for the negative isotope effect previously reported [1]. The success of the semi-classical simulations suggests that non-Fermi liquid effects are not required to explain the interlayer-transport in this system.
Journal of Physics: Condensed Matter | 2005
Ross D. McDonald; John Singleton; Paul Goddard; F Drymiotis; N. Harrison; Hisatomo Harima; M-T Suzuki; Avadh Saxena; Timothy W. Darling; Albert Migliori; J. L. Smith; J. C. Lashley
Martensites are materials that undergo diffusionless, solid-state transitions. The martensitic transition yields properties that depend on the history of the material and may allow it to recover its previous shape after plastic deformation. This is known as the shape-memory effect (SME). We have succeeded in identifying the primary electronic mechanism responsible for the martensitic transition in the shape-memory alloy AuZn by using Fermi-surface measurements (de Haas–van Alphen oscillations) and band-structure calculations. This strongly suggests that electronic band structure is an important consideration in the design of future SME alloys.
Synthetic Metals | 2005
A. Bangura; Paul Goddard; S.W. Tozer; Amalia I. Coldea; Ross D. McDonald; John Singleton; Arzhang Ardavan; J. Schleuter
Journal of Physics and Chemistry of Solids | 2006
Ross D. McDonald; Paul Goddard; J. C. Lashley; N. Harrison; Charles H. Mielke; John Singleton; Hisatomo Harima; Michi-To Suzuki
Archive | 2017
John Singleton; Jae Wook Kim; Craig V. Topping; Anders Hansen; Eun Duk Mun; Shalinee Chikara; I. Lakis; Saman Ghannadzadeh; Paul Goddard; Xuan Luo; Sang-Wook Cheong; Vivien Zapf
Archive | 2016
Jamie L. Manson; John A. Schlueter; Kerry E. Garrett; Paul Goddard; Tom Lancaster; Johannes Möller; Stephen J. Blundell; Andrew J. Steele; Isabel Franke; Francis L. Pratt; John Singleton; Jesper Bendix; Saul H. Lapidus; Marc Uhlarz; Oscar Ayala-Valenzuela; Ross D. McDonald; Mary Gurak; Christopher Baines
Archive | 2016
Joydeb Goura; Jamie Brambleby; Craig V. Topping; Paul Goddard; Ramakirushnan Suriya Narayanan; Arun Kumar Bar; Vadapalli Chandrasekhar
Archive | 2016
P.-C. Ho; John Singleton; Paul Goddard; Fedor Balakirev; Chikara Shalinee; Tatsuya Yanagisawa; M. Brian Maple; David B. Shrekenhamer; Xia Lee; Avraham T. Thomas
Archive | 2016
Paul Goddard; John Singleton; Isabel Franke; Johannes Möller; Tom Lancaster; Andrew J. Steele; Craig V. Topping; Stephen J. Blundell; Francis L. Pratt; C. Baines; Jesper Bendix; Ross D. McDonald; Jamie Brambleby; Martin R. Lees; Saul H. Lapidus; Peter W. Stephens; Brendan Twamley; Marianne M. Conner; K. A. Funk; Jordan F. Corbey; Hope E. Tran; John A. Schlueter; Jamie L. Manson