Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 7 of 7
Full-Text Articles in Entire DC Network
Coherent Coupling Between Exciton Resonances Governed By The Disorder Potential, Yuri D. Glinka, Zheng Sun, Mikhail Erementchouk, Michael N. Leuenberger, Alan D. Bristow, Steven T. Cundiff, Allan S. Bracker, Xiaoqin Li
Coherent Coupling Between Exciton Resonances Governed By The Disorder Potential, Yuri D. Glinka, Zheng Sun, Mikhail Erementchouk, Michael N. Leuenberger, Alan D. Bristow, Steven T. Cundiff, Allan S. Bracker, Xiaoqin Li
Faculty Bibliography 2010s
Monolayer fluctuations in the thickness of a semiconductor quantum well (QW) lead to the formation of spectrally resolved excitons located in the narrower, average, and thicker regions of the QW. Whether or not these excitons are coherently coupled via Coulomb interaction is a long-standing debate. We demonstrate that different types of disorder potential govern coherent coupling among excitons, and the coupling strength can be quantitatively measured using optical two-dimensional Fourier transform spectroscopy. Strong coherent coupling occurs between certain types of excitons but is missing between other types of excitons because the distinctive nature of excitons results in different spatial overlap. …
Anomalous Angular Dependence Of The Upper Critical Induction Of Orthorhombic Ferromagnetic Superconductors With Completely Broken P-Wave Symmetry, Christopher Lörscher, Jingchuan Zhang, Qiang Gu, Richard A. Klemm
Anomalous Angular Dependence Of The Upper Critical Induction Of Orthorhombic Ferromagnetic Superconductors With Completely Broken P-Wave Symmetry, Christopher Lörscher, Jingchuan Zhang, Qiang Gu, Richard A. Klemm
Faculty Bibliography 2010s
We employ the Klemm-Clem transformations to map the equations of motion for the Green functions of a clean superconductor with a general ellipsoidal Fermi surface (FS) characterized by the effective masses m(1), m(2), and m(3) in the presence of an arbitrarily directed magnetic induction B = B( sin theta cos phi, sin theta sin phi, cos theta) onto those of a spherical FS. We then obtain the transformed gap equation for a transformed pairing interaction (V) over tilde ((sic), (sic)') appropriate for any orbital order parameter symmetry. We use these results to calculate the upper critical induction B-c2(theta, phi) for …
Kinetically Driven Shape Changes In Early Stages Of Two-Dimensional Island Coarsening: Ag/Ag(111), Giridhar Nandipati, Abdelkader Kara, Syed Islamuddin Shah, Talat S. Rahman
Kinetically Driven Shape Changes In Early Stages Of Two-Dimensional Island Coarsening: Ag/Ag(111), Giridhar Nandipati, Abdelkader Kara, Syed Islamuddin Shah, Talat S. Rahman
Faculty Bibliography 2010s
We present here a detailed analysis of the shapes of two-dimensional Ag islands of various sizes observed during the early stages of coarsening on the Ag(111) surface, using kinetic Monte Carlo (KMC) simulations, and show that selectivity is due to the formation of kinetically stable island shapes that survive longer than nonselected sizes, which decay into nearby selected sizes. The stable shapes have a closed-shell structure-one in which every atom on the periphery has at least three nearest neighbors. These findings further explain our earlier study in which we found that in the early stages coarsening proceeds as a sequence …
Three-Dimensional Topological Insulator Quantum Dot For Optically Controlled Quantum Memory And Quantum Computing, Hari P. Paudel, Michael N. Leuenberger
Three-Dimensional Topological Insulator Quantum Dot For Optically Controlled Quantum Memory And Quantum Computing, Hari P. Paudel, Michael N. Leuenberger
Faculty Bibliography 2010s
We present the model of a quantum dot (QD) consisting of a spherical core-bulk heterostructure made of three-dimensional (3D) topological insulator (TI) materials, such as PbTe/Pb0.31Sn0.69Te, with bound massless and helical Weyl states existing at the interface and being confined in all three dimensions. The number of bound states can be controlled by tuning the size of the QD and the magnitude of the core and bulk energy gaps, which determine the confining potential. We demonstrate that such bound Weyl states can be realized for QD sizes of few nanometers. We identify the spin locking and the Kramers pairs, both …
Self-Diffusion Of Small Ni Clusters On The Ni(111) Surface: A Self-Learning Kinetic Monte Carlo Study, Syed Islamuddin Shah, Giridhar Nandipati, Abdelkader Kara, Talat S. Rahman
Self-Diffusion Of Small Ni Clusters On The Ni(111) Surface: A Self-Learning Kinetic Monte Carlo Study, Syed Islamuddin Shah, Giridhar Nandipati, Abdelkader Kara, Talat S. Rahman
Faculty Bibliography 2010s
We have examined the self-diffusion of small 2D Ni islands (consisting of up to 10 atoms) on the Ni(111) surface using a self-learning kinetic Monte Carlo (SLKMC-II) method with an improved pattern-recognition scheme that allows inclusion of both fcc and hcp sites in the simulations. Activation energy barriers for the identified diffusion processes were calculated on the fly using a semiempirical interaction potential based on the embedded-atom method. Although a variety of concerted, multiatom, and single-atom processes were automatically revealed in our simulations, we found that, in the temperature range of 300 K-700 K, these small islands diffuse primarily via …
Dark-Field Transmission Electron Microscopy And The Debye-Waller Factor Of Graphene, Brian Shevitski, Matthew Mecklenburg, Willaim A. Hubbard, E. R. White, Ben Dawson, M. S. Lodge, Masa Ishigami, B. C. Regan
Dark-Field Transmission Electron Microscopy And The Debye-Waller Factor Of Graphene, Brian Shevitski, Matthew Mecklenburg, Willaim A. Hubbard, E. R. White, Ben Dawson, M. S. Lodge, Masa Ishigami, B. C. Regan
Faculty Bibliography 2010s
Graphene's structure bears on both the material's electronic properties and fundamental questions about long-range order in two-dimensional crystals. We present an analytic calculation of selected area electron diffraction from multilayer graphene and compare it with data from samples prepared by chemical vapor deposition and mechanical exfoliation. A single layer scatters only 0.5% of the incident electrons, so this kinematical calculation can be considered reliable for five or fewer layers. Dark-field transmission electron micrographs of multilayer graphene illustrate how knowledge of the diffraction peak intensities can be applied for rapid mapping of thickness, stacking, and grain boundaries. The diffraction peak intensities …
Heat Transfer Mechanism Across Few-Layer Graphene By Molecular Dynamics, Meng Shen, Patrick K. Schelling, Pawel Keblinski
Heat Transfer Mechanism Across Few-Layer Graphene By Molecular Dynamics, Meng Shen, Patrick K. Schelling, Pawel Keblinski
Faculty Bibliography 2010s
We use nonequilibrium molecular dynamics to study heat transfer across structures consisting of a few layers of graphene sandwiched between silicon crystals. We find that when heat transfers from a silicon lead on one side across the graphene layers to a silicon lead on the other side, the interfacial conductance is essentially independent of the number of layers, in agreement with recent experimental findings. By contrast, wave-packet simulations show that the transmission coefficient of individual vibrational modes depends strongly on frequency and the number of graphene layers, indicating significant interference effects. This apparent contradiction is resolved by a theoretical calculation, …