Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 6 of 6
Full-Text Articles in Physics
Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen
Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen
Physics & Astronomy Faculty Research
Diamond is the quintessential superhard material widely known for its stiff and brittle nature and large electronic band gap. In stark contrast to these established benchmarks, our first-principles studies unveil surprising intrinsic structural ductility and electronic conductivity in diamond under coexisting large shear and compressive strains. These complex loading conditions impede brittle fracture modes and promote atomistic ductility, triggering rare smooth plastic flow in the normally rigid diamond crystal. This extraordinary structural change induces a concomitant band gap closure, enabling smooth charge flow in deformation created conducting channels. These startling soft-and-conducting modes reveal unprecedented fundamental characteristics of diamond, with profound …
Gamma-Ray Bursts Induced By Turbulent Reconnection, A. Lazarian, Bing Zhang, Siyao Xu
Gamma-Ray Bursts Induced By Turbulent Reconnection, A. Lazarian, Bing Zhang, Siyao Xu
Physics & Astronomy Faculty Research
We revisit the Internal-Collision-induced MAgnetic Reconnection and Turbulence model of gamma-ray bursts (GRBs) in view of the advances made in understanding of both relativistic magnetic turbulence and relativistic turbulent magnetic reconnection. We identify the kink instability as the most natural way of changing the magnetic configuration to release the magnetic free energy through magnetic reconnection, as well as driving turbulence that enables fast turbulent reconnection. We show that this double role of the kink instability is important for explaining the prompt emission of GRBs. Our study confirms the critical role that turbulence plays in boosting reconnection efficiency in GRBs and …
Rotational Quenching Of Hd Induced By Collisions With H2 Molecules, Yier Wan, Nadulvalath Balakrishnan, B. H. Yang, R. C. Forrey, P. C. Stancil
Rotational Quenching Of Hd Induced By Collisions With H2 Molecules, Yier Wan, Nadulvalath Balakrishnan, B. H. Yang, R. C. Forrey, P. C. Stancil
Chemistry and Biochemistry Faculty Research
Rate coefficients for rotational transitions in HD induced by H2 impact for rotational levels of HD j ≤ 8 and temperatures 10 K ≤ T ≤ 5000 K are reported. The quantum mechanical close-coupling (CC) method and the coupled-states (CS) decoupling approximation are used to obtain the cross-sections employing the most recent highly accurate H2–H2 potential energy surface (PES). Our results are in good agreement with previous calculations for low-lying rotational transitions The cooling efficiency of HD compared with H2 and astrophysical applications are briefly discussed.
The Purported Square Ice In Bilayer Graphene In A Nanoscale, Monolayer Object, Tod A. Pascal, Craig P. Schwartz, Keith V. Lawler, David Prendergast
The Purported Square Ice In Bilayer Graphene In A Nanoscale, Monolayer Object, Tod A. Pascal, Craig P. Schwartz, Keith V. Lawler, David Prendergast
Chemistry and Biochemistry Faculty Research
The phase diagram of water is complex, and interfacial effects can stabilize unusual structures at the nanoscale. Here, we employ bond order accelerated molecular dynamics simulations to show that upon encapsulation within bilayer graphene, water can spontaneously adopt a two-dimensional (monomolecular) layer of “square ice” at ambient conditions, instead of an encapsulated water droplet. Free energy calculations show that this motif is thermodynamically stable up to diameters of approximately 15 nm due to enhanced hydrogen bonding and favorable binding to the graphene sheets. Entropic losses due to solidification and reduced graphene–graphene binding enthalpy are opposing thermodynamic forces that conspire to …
Controlling The Stereodynamics Of Cold Molecular Collisions, Balakrishnan Naduvalath, J. F. E. Croft, Meng Huang, Hua Guo
Controlling The Stereodynamics Of Cold Molecular Collisions, Balakrishnan Naduvalath, J. F. E. Croft, Meng Huang, Hua Guo
Chemistry and Biochemistry Faculty Research
We report numerically-exact quantum scattering calculations for low-energy collisions of quantum-state prepared HD with H2. Excellent agreement is obtained with recent measurements of Perreault et al. for the angular distribution of scattered HD at a collision energy of 1 K. By state-preparation of the HD molecules, control of the angular distribution of scattered HD was demonstrated. The stereo-dynamic control is achieved by the ability to choose a single or a coherent superposition of quantum states. We present a first-principles simulation of the experiment which enables us to attribute the main features of the observed angular distribution to a single L …
Kondo Signatures Of A Quantum Magnetic Impurity In Topological Superconductors, Rui Wang, Wei-Yi Su, Jian-Xin Zhu, Chin-Sen Ting, Hai Li, Changfeng Chen, Baigeng Wang, Xiaoqun Wang
Kondo Signatures Of A Quantum Magnetic Impurity In Topological Superconductors, Rui Wang, Wei-Yi Su, Jian-Xin Zhu, Chin-Sen Ting, Hai Li, Changfeng Chen, Baigeng Wang, Xiaoqun Wang
Physics & Astronomy Faculty Research
We study the Kondo physics of a quantum magnetic impurity in two-dimensional topological superconductors (TSCs), either intrinsic or induced on the surface of a bulk topological insulator, using a numerical renormalization group technique. We show that, despite sharing the p+ip pairing symmetry, intrinsic and extrinsic TSCs host different physical processes that produce distinct Kondo signatures. Extrinsic TSCs harbor an unusual screening mechanism involving both electron and orbital degrees of freedom that produces rich and prominent Kondo phenomena, especially an intriguing pseudospin Kondo singlet state in the superconducting gap and a spatially anisotropic spin correlation. In sharp contrast, intrinsic TSCs support …