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Full-Text Articles in Physics
A Low Temperature Nonlinear Optical Rotational Anisotropy Spectrometer For The Determination Of Crystallographic And Electronic Symmetries, Darius H. Torchinsky, Hao Chu, Tongfei Qi, Gang Cao, David Hsieh
A Low Temperature Nonlinear Optical Rotational Anisotropy Spectrometer For The Determination Of Crystallographic And Electronic Symmetries, Darius H. Torchinsky, Hao Chu, Tongfei Qi, Gang Cao, David Hsieh
Center for Advanced Materials Faculty Publications
Nonlinear optical generation from a crystalline material can reveal the symmetries of both its lattice structure and underlying ordered electronic phases and can therefore be exploited as a complementary technique to diffraction based scattering probes. Although this technique has been successfully used to study the lattice and magnetic structures of systems such as semiconductor surfaces, multiferroic crystals, magnetic thin films, and multilayers, challenging technical requirements have prevented its application to the plethora of complex electronic phases found in strongly correlated electron systems. These requirements include an ability to probe small bulk single crystals at the μm length scale, a need …
Transparent Conducting Oxides: A Δ-Doped Superlattice Approach, Valentino R. Cooper, Sung S. Ambrose Seo, Suyoun Lee, Jun Sung Kim, Woo Seok Choi, Satoshi Okamoto, Ho Nyung Lee
Transparent Conducting Oxides: A Δ-Doped Superlattice Approach, Valentino R. Cooper, Sung S. Ambrose Seo, Suyoun Lee, Jun Sung Kim, Woo Seok Choi, Satoshi Okamoto, Ho Nyung Lee
Physics and Astronomy Faculty Publications
Metallic states appearing at interfaces between dissimilar insulating oxides exhibit intriguing phenomena such as superconductivity and magnetism. Despite tremendous progress in understanding their origins, very little is known about how to control the conduction pathways and the distribution of charge carriers. Using optical spectroscopic measurements and density-functional theory (DFT) simulations, we examine the effect of SrTiO3 (STO) spacer layer thickness on the optical transparency and carrier distribution in La δ-doped STO superlattices. We experimentally observe that these metallic superlattices remain highly transparent to visible light; a direct consequence of the appropriately large gap between the O 2p and Ti 3d …
Ferromagnetic Resonance Study Of Eightfold Artificial Ferromagnetic Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, J. Woods, B. Farmer, J. B. Ketterson, Jeffrey Todd Hastings, Lance E. De Long
Ferromagnetic Resonance Study Of Eightfold Artificial Ferromagnetic Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, J. Woods, B. Farmer, J. B. Ketterson, Jeffrey Todd Hastings, Lance E. De Long
Physics and Astronomy Faculty Publications
We have performed broadband (10 MHz–18 GHz) and narrowband (9.7 GHz) ferromagnetic resonance (FMR) measurements on permalloy thin films patterned with quasiperiodic Ammann tilings having eightfold rotational symmetry. We observed highly reproducible mode structures in the low-frequency, hysteretic regime in which domain walls and unsaturated magnetization textures exist. A minimum of 10 robust modes were observed in patterned samples, compared to the single uniform mode observed in unpatterned permalloy films. The field dependence and approximate eightfold rotational symmetry of the FMR spectra are in good agreement with micromagnetic simulations that confirm the importance of patterning for controlling static and dynamic …
Tunneling Into The Mott Insulator Sr2Iro4, John A. Nichols, Noah Bray-Ali, Armin Ansary, Gang Cao, Kwok-Wai Ng
Tunneling Into The Mott Insulator Sr2Iro4, John A. Nichols, Noah Bray-Ali, Armin Ansary, Gang Cao, Kwok-Wai Ng
Center for Advanced Materials Faculty Publications
We studied the single-layered iridate Sr2IrO4 with a scanning tunneling microscope. The finite low temperature conductance enables the electronic structure of this antiferromagnetic Mott insulator to be measured by tunneling spectroscopy. We imaged the topography of freshly cleaved surfaces and measured differential tunneling conductance at cryogenic temperatures. We found the Mott gap in the tunneling density of states to be 2Δ=615 meV. Within the Mott gap, additional shoulders are observed which are interpreted as inelastic loss features due to magnons.