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Full-Text Articles in Physics

Isotope Effect On Electron-Phonon Interaction In Multiband Superconductor Mgb2, Adam Kaminski, Daixiang Mou, Paul C. Canfield, Serguei Budko, Lunan Huang, Valentin Taufour, Yun Wu, Soham Manni Apr 2016

Isotope Effect On Electron-Phonon Interaction In Multiband Superconductor Mgb2, Adam Kaminski, Daixiang Mou, Paul C. Canfield, Serguei Budko, Lunan Huang, Valentin Taufour, Yun Wu, Soham Manni

Ames Laboratory Datasets

We investigate the effect of isotope substitution on electron-phonon interaction in multi-band superconductor MgB$_2$ using tunable laser based Angle Resolved Photoemission Spectroscopy. The kink structure around 70 meV in Sigma band, which is caused by electron coupling to E_2g phonon mode, is shifted to higher binding energy by ~3.5 meV in Mg^10B2. The changes of the kink energy reported here suggest that the anharmonicity of the E2g phonon in MgB2 is very small, which reopens the debate about the unusually small isotope coefficient in this material. These results are the benchmark for investigation of isotope effect in ...


Discovery Of Dirac Node Arcs In Ptsn4, Adam Kaminski, Paul C. Canfield, Serguei Bud'ko, Daixiang Mou, Eundeok Mun, Yun Wu, Lunan Huang, Yongbin Lee, Duane D. Johnson, Linlin Wang Jan 2016

Discovery Of Dirac Node Arcs In Ptsn4, Adam Kaminski, Paul C. Canfield, Serguei Bud'ko, Daixiang Mou, Eundeok Mun, Yun Wu, Lunan Huang, Yongbin Lee, Duane D. Johnson, Linlin Wang

Ames Laboratory Datasets

In topological quantum materials the conduction and valence bands are connected at points (Dirac/Weyl semimetals) or along lines (Line Node semimetals) in the momentum space. Numbers of studies demonstrated that several materials are indeed Dirac/Weyl semimetals. However, there is still no experimental confirmation of materials with line nodes, in which the Dirac nodes form closed loops in the momentum space. Here we report the discovery of a novel topological structure - Dirac node arcs - in the ultrahigh magnetoresistive material PtSn4 using laser-based angle-resolved photoemission spectroscopy (ARPES) data and density functional theory (DFT) calculations. Unlike the closed loops of line ...


Imaging The Magnetic Nano-Domains In Nd2fe14b, Adam Kaminski, Daixiang Mou, Paul C. Canfield, Valentin Taufour, Lunan Huang, Serguei Budko, Benjamin Schrunk, Tey Lamichhane Jan 2016

Imaging The Magnetic Nano-Domains In Nd2fe14b, Adam Kaminski, Daixiang Mou, Paul C. Canfield, Valentin Taufour, Lunan Huang, Serguei Budko, Benjamin Schrunk, Tey Lamichhane

Ames Laboratory Datasets

We study magnetic domains in Nd2Fe14B single crystals using high resolution magnetic force microscopy (MFM). Previous MFM studies and small angle neutron scattering experiments suggested the presence of nano-scale domains in addition to optically detected micrometer-scale ones. We find, in addition to the elongated, wavy nano-domains reported by a previous MFM study, that the micrometer size, star shape fractal pattern is constructed of an elongated network of nano-domains ~20 nm in width, with resolution-limited domain walls thinner than 2 nm. While the microscopic domains exhibit significant resilience to an external magnetic field, some of the nano domains are sensitive to ...