Read by QxMD icon Read

topological phases

Yinghai Wu, Tao Shi, Jainendra K Jain
The current proposals for producing non-Abelian anyons and Majorana particles, which are neither fermions nor bosons, are primarily based on the realization of topological superconductivity in two dimensions. We show theoretically that the unique Landau level structure of bilayer graphene provides a new possible avenue for achieving such exotic particles. Specifically, we demonstrate the feasibility of a ``parton" fractional quantum Hall (FQH) state, which supports non-Abelian particles without the usual topological superconductivity...
June 26, 2017: Nano Letters
Soma Banik, Pranab Kumar Das, Azzedine Bendounan, Ivana Vobornik, A Arya, Nathan Beaulieu, Jun Fujii, A Thamizhavel, P U Sastry, A K Sinha, D M Phase, S K Deb
Rashba spin-orbit splitting in the magnetic materials opens up a new perspective in the field of spintronics. Here, we report a giant Rashba spin-orbit splitting on the PrGe [010] surface in the paramagnetic phase with Rashba coefficient α R  = 5 eVÅ. We find that α R can be tuned in this system as a function of temperature at different magnetic phases. Rashba type spin polarized surface states originates due to the strong hybridization between Pr 4f states with the conduction electrons. Significant changes observed in the spin polarized surface states across the magnetic transitions are due to the competition between Dzyaloshinsky-Moriya interaction and exchange interaction present in this system...
June 23, 2017: Scientific Reports
Adhip Agarwala, Vijay B Shenoy
Much of the current understanding of topological insulators, which informs the experimental search for topological materials and systems, is based on crystalline band theory, where local electronic degrees of freedom at different crystal sites hybridize with each other in ways that produce nontrivial topology. Here we provide a novel theoretical demonstration of realizing topological phases in amorphous systems, as exemplified by a set of sites randomly located in space. We show this by constructing hopping models on such random lattices whose gapped ground states are shown to possess nontrivial topological nature (characterized by Bott indices) that manifests as quantized conductances in systems with a boundary...
June 9, 2017: Physical Review Letters
M Eric Tai, Alexander Lukin, Matthew Rispoli, Robert Schittko, Tim Menke, Dan Borgnia, Philipp M Preiss, Fabian Grusdt, Adam M Kaufman, Markus Greiner
The interplay between magnetic fields and interacting particles can lead to exotic phases of matter that exhibit topological order and high degrees of spatial entanglement. Although these phases were discovered in a solid-state setting, recent innovations in systems of ultracold neutral atoms-uncharged atoms that do not naturally experience a Lorentz force-allow the synthesis of artificial magnetic, or gauge, fields. This experimental platform holds promise for exploring exotic physics in fractional quantum Hall systems, owing to the microscopic control and precision that is achievable in cold-atom systems...
June 21, 2017: Nature
Woon Yong Sohn, Sana Habka, Eric Gloaguen, Michel Mons
The presence in crystallized proteins of a local anchoring between the side chain of a His residue, located in the central position of a γ- or β-turn, and its local main chain environment, was assessed by the comparison of protein structures with relevant isolated model peptides. Gas phase laser spectroscopy, combined with relevant quantum chemistry methods, was used to characterize the γ- and β-turn structures in these model peptides. A conformer-selective NH stretch infrared study provided evidence for the formation in vacuo of two types of short-range H-bonded motifs, labelled ε-6(δ) and δ-(δ)7/π(H), bridging the His side chain (in its gauche+ rotamer) to the neighbouring NH(i) and CO(i) sites of the backbone; each side chain-backbone motif was found to be specific of the tautomer (ε or δ) adopted by the His side chain in its neutral form...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
Badri Nath Singh, V Mohan Murali Achary, Varakumar Panditi, Sudhir K Sopory, Malireddy K Reddy
The topoisomerase II expression varies as a function of cell proliferation. Maximal topoisomerase II expression was tightly coupled to S phase and G2/M phase via both transcriptional and post-transcriptional regulation. Investigation in meiosis using pollen mother cells also revealed that it is not the major component of meiotic chromosomes, it seems to diffuse out once meiotic chromosomal condensation is completed. Synchronized tobacco BY-2 cell cultures were used to study the role of topoisomerase II in various stages of the cell cycle...
June 20, 2017: Plant Molecular Biology
Changming Liu, Jinsong Liu, Liting Niu, Xuli Wei, Kejia Wang, Zhengang Yang
Vortex beams have received considerable research interests both in optical and millimeter-wave domain since its potential to be utilized in the wireless communications and novel imaging systems. Many well-known optical beams have been demonstrated to carry orbital angular momentum (OAM), such as Laguerre-Gaussian beams and high-order Bessel beams. Recently, the radially symmetric Airy beams that exhibit an abruptly autofocusing feature are also demonstrated to be capable of carrying OAM in the optical domain...
June 20, 2017: Scientific Reports
Tao Du, Yue-Xun Li, Yan Li, He-Lin Lu, Hui Zhang
The dimerized Kane-Mele model with/without the strong interaction is studied using analytical methods. The boundary of the topological phase transition of the model without strong interaction is obtained. Our results show that the occurrence of the transition only depends on dimerized parameter α . From the one-particle spectrum, we obtain the completed phase diagram including the quantum spin Hall (QSH) state and the topologically trivial insulator. Then, using different mean-field methods, we investigate the Mott transition and the magnetic transition of the strongly correlated dimerized Kane-Mele model...
June 20, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Pardis Rofouie, Damiano Pasini, Alejandro D Rey
Liquid crystalline phases found in many biological materials, such as actin, DNA, cellulose, and collagen can be responsible for the deformation of cell membranes. In this paper, cell membrane deformation is investigated through the coupling between liquid crystal anisotropy and membrane bending elasticity. The generalized shape equation for anisotropic interfaces, which resort to the Cahn-Hoffman capillarity vector, the Rapini-Papoular anchoring energy, and the Helfrich elastic energy, is applied to gain insight into the deformation of closed liquid crystal membranes...
June 20, 2017: Soft Matter
José A Sánchez-Rodríguez, Abed Mohamadzade, Sebastian Mai, Brennan Ashwood, Marvin Pollum, Philipp Marquetand, Leticia González, Carlos E Crespo-Hernández, Susanne Ullrich
Single-atom substitution within a natural nucleobase-such as replacing oxygen by sulfur in uracil-can result in drastic changes in the relaxation dynamics after UV excitation. While the photodynamics of natural nucleobases like uracil are dominated by pathways along singlet excited states, the photodynamics of thiobases like 2-thiouracil populate the triplet manifold with near unity quantum yield. In the present study, a synergistic approach based on time-resolved photoelectron spectroscopy (TRPES), time-resolved absorption spectroscopy (TRAS), and ab initio computations has been particularly successful at unraveling the underlying photophysical principles and describing the dissimilarities between the natural and substituted nucleobases...
June 20, 2017: Physical Chemistry Chemical Physics: PCCP
Christian Riesch, Günter Radons, Robert Magerle
We investigate the non-equilibrium dynamics of an ordered stripe-forming system free of topological defects. In particular, we study the ageing and the coarsening of orientation fluctuations parallel and perpendicular to the stripes via computer simulations based on a minimal phase-field model (model B with Coulomb interactions). Under the influence of noise, the stripe orientation field develops fluctuations parallel to the stripes, with the dominant modulation length λ*∥ increasing with time t as λ*∥ ∼ t(1/4) and the correlation length perpendicular to the stripes ξ(⊥)θ increasing as ξ(⊥)θ ∼ t(1/2)...
August 6, 2017: Interface Focus
Douglas M Hall, Gregory M Grason
Chirality frustrates and shapes the assembly of flexible filaments in rope-like, twisted bundles and fibres by introducing gradients of both filament shape (i.e. curvature) and packing throughout the structure. Previous models of chiral filament bundle formation have shown that this frustration gives rise to several distinct morphological responses, including self-limiting bundle widths, anisotropic domain (tape-like) formation and topological defects in the lateral inter-filament order. In this paper, we employ a combination of continuum elasticity theory and discrete filament bundle simulations to explore how these distinct morphological responses compete in the broader phase diagram of chiral filament assembly...
August 6, 2017: Interface Focus
Yonghua Wang, Min Rui, Guanghua Lu
Metal-organic frameworks are promising materials in diverse analytical applications especially in sample pretreatment by virtue of their diverse structure topology, tunable pore size, permanent nanoscale porosity, high surface area and good thermostability. According to hydrostability, metal-organic frameworks are divided into moisture-sensitive and water-stable types. In the actual application, both kinds of metal organic frameworks are usually engineered into hybrid composites containing magnetite, silicon dioxide, graphene or directly carbonized to metal-organic-frameworks-derived carbon...
June 19, 2017: Journal of Separation Science
Goran Isić, Slobodan Vuković, Zoran Jašić, Milivoj Belić
We analyze the fundamental properties of optical waves referred to as Tamm plasmon modes (TPMs) which are tied to the interface of a semi-infinite two-phase metallodielectric superlattice with an arbitrary homogeneous capping medium. Such modes offer new ways of achieving high electromagnetic field localization and spontaneous emission enhancement in the vicinity of the interface in conjunction with absorption loss management, which is crucial for future applications. The homointerface, formed when the capping medium has the same permittivity as one of the superlattice constituents, is found to support a TPM whose dispersion overlaps the single-interface surface plasmon polariton (SPP) dispersion but which has a cut off at the topological transition point...
June 16, 2017: Scientific Reports
Tetsuya Takahashi, Teruya Yamanishi, Sou Nobukawa, Shinya Kasakawa, Yuko Yoshimura, Hirotoshi Hiraishi, Chiaki Hasegawa, Takashi Ikeda, Tetsu Hirosawa, Toshio Munesue, Haruhiro Higashida, Yoshio Minabe, Mitsuru Kikuchi
OBJECTIVE: Altered brain connectivity has been theorized as a key neural underpinning of autism spectrum disorder (ASD), but recent investigations have revealed conflicting patterns of connectivity, particularly hyper-connectivity and hypo-connectivity across age groups. The application of graph theory to neuroimaging data has become an effective approach for characterizing topographical patterns of large-scale functional networks. We used a graph approach to investigate alteration of functional networks in childhood ASD...
May 23, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Bitan Roy, Yahya Alavirad, Jay D Sau
We investigate the phase diagram of a three-dimensional, time-reversal symmetric topological superconductor in the presence of charge impurities and random s-wave pairing. Combining complimentary field theoretic and numerical methods, we show that the quantum phase transition between two topologically distinct paired states (or thermal insulators), described by thermal Dirac semimetal, remains unaffected in the presence of sufficiently weak generic randomness. At stronger disorder, however, these two phases are separated by an intervening thermal metallic phase of diffusive Majorana fermions...
June 2, 2017: Physical Review Letters
Guillem Aromi, Jorge Salinas-Uber, Marta Estrader, Jordi Garcia, Paul Lloyd-Williams, Anna Sadurní, Dominik Dengler, Joris van Slageren, Nicholas Chilton, Olivier Roubeau, Simon Teat, Jordi Ribas-Ariño
Controlling the charges and spins of molecules lyes at the heart of spintronics. We report the design of a photoswitchable molecule consisting of two independent spins separated by a photo-switchable moiety contained within a new ligand, H4L, that features a dithienylethene photochromic unit and two lateral coordinating moieties, yielding molecules with the [MM···MM] topology. Compounds [M4L2(py)6] (M = Cu, 1; Co, 2; Ni, 3; Zn, 4) have been prepared and described by single crystal X-ray diffraction (SCXRD)...
June 16, 2017: Chemistry: a European Journal
Biswajit Das, Nirmalya Sankar Das, Samrat Sarkar, Biplab Kr Chatterjee, Kalyan Kumar Chattopadhyay
Chemically derived topological insulator Bi2Se3nanoflake/ Si nanowire (SiNWs) heterojunctions were fabricated employing all eco-friendly cost effective chemical route for the first time. X-ray diffraction studies confirmed proper phase formation of Bi2Se3nanoflakes. The morphological features of the individual components and time evolved hybrid structures were studied using field emission scanning electron microscope. High resolution transmission electronic microscopic studies were performed to investigate the actual nature of junction whereas elemental distributions at junction along with overall stoichiometry of the samples were analyzed using energy dispersive x-ray studies...
June 16, 2017: ACS Applied Materials & Interfaces
Jose A Martínez-González, Xiao Li, Monirosadat Sadati, Ye Zhou, Rui Zhang, Paul F Nealey, Juan J de Pablo
Chiral nematic liquid crystals are known to form blue phases-liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate...
June 16, 2017: Nature Communications
Sheng-Shi Li, Wei-Xiao Ji, Ping Li, Shu-Jun Hu, Li Cai, Chang-Wen Zhang, Shi-Shen Yan
The quantum spin Hall (QSH) effect is promising for achieving dissipationless transport devices due to their robust gapless edge states inside insulating bulk gap. However, the currently discussed QSH insulators usually suffer from ultrahigh vacuum or low temperature due to the small bulk gap, which limits their practical applications. Searching for large-gap QSH insulators is highly desirable. Here, the tunable QSH state of a Bi(110) films with a black phosphorus (BP) structure, which is robust against structural deformation and electric field, is explored by first-principles calculations...
June 15, 2017: ACS Applied Materials & Interfaces
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"