Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session P41: Nanowires and Quantum DotsLive
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Sponsoring Units: DCMP Chair: Alexandru Bogdan Georgescu, Simons Foundation |
Wednesday, March 17, 2021 3:00PM - 3:12PM Live |
P41.00001: Universal properties of anyon braiding on one-dimensional wire networks Tomasz Maciazek, Byung Hee An World lines of anyons that exchange in 2D form braids in spacetime. These braids are subject to certain universal topological relations coming from their continuous deformations. In 2D, such an approach leads to the well-known braiding relation also known as the Yang-Baxter relation. In my talk, I will show how to define counterparts of braids and derive braiding relations for anyons constrained to move on planar wire networks. In particular, I will demonstrate that anyons on wire networks have fundamentally different braiding properties than anyons in 2D. My analysis reveals an unexpectedly wide variety of possible non-abelian braiding behaviours on networks. The character of braiding depends on the topological invariant called the connectedness of the network. As one of our most striking consequences, particles on modular networks can change their statistical properties when moving between different modules. However, sufficiently highly connected networks already reproduce braiding properties of 2D systems. |
Wednesday, March 17, 2021 3:12PM - 3:24PM Live |
P41.00002: Tuning the Electro-Optical Properties of Nanowire Networks koorosh esteki, Hugh Manning, Mauro S. Ferreira, John Boland, Claudia Gomes da Rocha Metallic nanowire networks (NWNs) have attracted great attention as transparent conductors due to its high opto-electrical performance. Here we conducted an in-depth computational study of randomly oriented and grid patterned NWNs in which we obtain and compare their figures of merit (optical transmittance versus sheet resistance) for a variety of metallic materials. In addition, the impact of the nanowires’ alignment on the network electrical conductivity is studied. The optical transmittance calculations are carried out using Mie light scattering theory whereas the sheet resistance is determined using modified nodal analysis for a resistive circuit network. We have found that an optimum trade-off between optical transmittance and sheet resistance can be tuned by playing with the grid-pattern design of the networks, density, nanowire orientation, and material properties. Other relevant network parameters we have considered in our simulations include nanowire length and diameter, and coverage area fraction. The outcomes of this research will contribute to the design the transparent conductor devices made of metallic NWNs with optimal opto-electrical performance. |
Wednesday, March 17, 2021 3:24PM - 3:36PM Live |
P41.00003: Driving forces behind the distortion of one-dimensional monatomic chains: Peierls theorem revisited Uri Argaman, Daniela Kartoon, Guy Makov The onset of distortion in one-dimensional monatomic chains with partially filled valence bands is considered to be well established by the Peierls theorem, which associates the distortion with the formation of a band gap and a subsequent gain in energy. Employing modern total energy methods on the test cases of lithium, sodium, and carbon chains, we reveal that the distortion is not universal but conditional upon the balance between distorting and stabilizing forces. Furthermore, in all systems studied, the electrostatic interactions between the electrons and ions act as the main driving force for distortion, rather than the electron band lowering at the Fermi level as is commonly believed. The main stabilizing force which drives the chains toward their symmetric arrangement is derived from the electronic kinetic energy. Both forces are affected by the external conditions, e.g., stress, and consequently the instability of one-dimensional nanowires is conditional upon them. This brings a perspective to the field of one-dimensional metals and may shed light on the distortion of more complex structures. |
Wednesday, March 17, 2021 3:36PM - 3:48PM Live |
P41.00004: Monte Carlo simulation of critical phenomena near the percolation threshold in two-dimensional networks consisting of curvy nanowires Yunong Wang, Ant Ural Employing Monte Carlo simulations, we compute critical phenomena including the percolation probability and the critical curviness angle in 2D networks consisting of curvy nanowires. In most computational work, nanowires in 2D networks have been modeled as straight sticks. However, experimentally deposited nanowires exhibit some degree of curviness. We generate curved nanowires using third order Bezier curves characterized by the curviness angle. By computing percolation probability as a function of curviness angle at fixed nanowire density, we first extract the critical curviness angle at different densities using finite size scaling analysis. We find that the critical curviness angle increases with increasing density. Second, we find that nanowire alignment significantly changes the shape of the percolation probability versus curviness angle curve near the percolation threshold. We also extract the curl ratio critical exponent at the percolation threshold using finite size scaling. These results show that computational studies are an essential tool for providing insights into the insulator-to-conductor transition in nanowire networks, which are promising candidates for applications such as flexible transparent conductors, thin film transistors, and resistive switching memory. |
Wednesday, March 17, 2021 3:48PM - 4:00PM Live |
P41.00005: Edge State Wave-Functions and Velocities from Tunneling Spectroscopy Taras Patlatiuk, Christian Scheller, Daniel Hill, Yaroslav Tserkovnyak, Carlos Egues, Gilad Barak, Amir Yacoby, Loren Pfeiffer, Ken W. West, Dominik Zumbuhl We perform momentum-conserving tunneling spectroscopy using a GaAs cleaved-edge overgrowth quantum wire to investigate adjacent quantum Hall edge states [1]. We use the wire modes with their distinct wave functions to probe each edge state and apply B-fields to modify the wave functions and their overlap. This reveals an intricate and rich tunneling conductance fan structure which is succinctly different for each of the wire modes. We self-consistently solve the Poisson-Schrödinger equations to simulate the spectroscopy, reproducing the striking fans in great detail, thus, confirming the calculations. |
Wednesday, March 17, 2021 4:00PM - 4:12PM Live |
P41.00006: Coulomb drag between quantum wires in the quasi-1D regime Rebika Makaju, Harith Kassar, John L. Reno, Dominique Laroche We report Coulomb drag measurements in laterally-coupled single layer GaAs/AlGaAs quantum wires, enabling in situ tuning of their effective interwire separation. The drag resistance RD exhibits the standard modulation as the wires’ subband occupancy is varied. We mapped the temperature dependence of RD as a function of both subband occupancy and interwire separation in the quasi-1D regime were more than a single 1D subband is occupied. The qualitative and quantitative functional shape of this dependence is utilized to determine the parametric evolution of the dominant drag inducing scattering mechanism and of the strength of electron-electron interactions, respectively. |
Wednesday, March 17, 2021 4:12PM - 4:24PM Live |
P41.00007: Enhanced Dresselhaus spin-orbit interaction in low-symmetry nanowires Miguel Carballido, Christoph Kloeffel, Dominik Zumbuhl, Daniel Loss Semiconducting nanowires (NWs) are promising building blocks for solid-state quantum computers, since they allow for conventional spin and charge qubits as well as for topological quantum computing schemes. Such systems often rely on spin-orbit interaction (SOI), which is a crucial mechanism in modern fields of condensed matter physics. |
Wednesday, March 17, 2021 4:24PM - 4:36PM Live |
P41.00008: Synthesis of Cobalt Oxide Based Misfit Nanotubes with High Conductivity and Ampacity. Kankona Singha Roy, Saurabh Lodha, Leela Srinivas Panchakarla With increasing miniaturization of modern devices the requirement of current to flow through narrow channel has escalated. So, systems with both high ampacity and high conductivity is in demand. We choose calcium cobaltite (CCO) and strontium cobaltite (SCO)- misfit complex oxide which have gained interest due to their high conductivity and low thermal conductivity. We present the synthesis of 1D nanotubes (NT) from oxide misfit compounds with a very high yield by solid-state and solution-based synthesis. When investigated electrical property it is found that CCO nanotubes are of p-type semiconductor and the ampacity of these nanotubes is around 6.5*105 A/cm2. But surprisingly, in the case of SCO nanotube, it shows a very high current carrying capacity of 0.88*108 A/cm2 for a single NT. These values are comparable to metals as well as to CNT and is proven to be one of the best oxide based material among inorganic materials. Temperature dependent resistivity measurements indicates a voltage-induced semiconductor to metal transition in the case of SCO NTs. These results demonstrate that the high conductivity of these nanotubes could be a potential building block for future modern devices. |
Wednesday, March 17, 2021 4:36PM - 4:48PM Live |
P41.00009: Room temperature GeSn nanowire mid-infrared photodetectors Lu Luo, Simone Assali, Mahmoud R. M. Atalla, Sebastian Koelling, Oussama Moutanabbir Germanium-Tin (GeSn) alloys have recently been the subject of extensive investigations as new material systems to engineer a direct bandgap in group IV semiconductors, which will pave the way to developing silicon-compatible photonic, electronic and optoelectronic devices. The same paradigm can be extended to grow nanowires (NWs) and NW heterostructures, thus providing additional degrees of freedom to tailor the basic properties of this emerging class of semiconductors. Careful control of the growth kinetics to incorporate Sn atoms into Ge at concentrations about one order of magnitude higher than the equilibrium solubility is at the core of this technology. In this presentation, we will discuss the structural and opto-electronic properties of Ge/GeSn core/shell nanowires (NW) that are grown with a tunable, uniform Sn content exceeding 20 at.%. Single NW photodetectors operating at short-wave infrared (SWIR) and mid-infrared (MIR) wavelengths will be shown at room temperature and their properties will be investigated at cryogenic temperatures. By simultaneously increasing Sn content and minimizing strain in the GeSn shell, the absorption edge in the photocurrent measurements can be precisely tuned from ~2 μm (8 at.%) to longer MIR wavelengths. |
Wednesday, March 17, 2021 4:48PM - 5:00PM Live |
P41.00010: Rolling up Two-Dimensional Layers of Silicon Sulfide:
Dimerization Effects and Negative Strain Energy in Silicon Monosulfide Nanotubes Tomas Alonso-Lanza, Faustino Aguilera-Granja, Andres Ayuela We investigate nanotubes of two-dimensional materials isoelectronic to phosphorene by rolling up the recently discovered layers of silicon monosulfide, in phases that in order of decreasing stability are labeled as Pmma and β [1-3]. We find that the nanotubes of thick layer Pmma silicon monosulfide grown around 1 nm in diameter are stable at room temperature. The nanotubes having small diameters show metallic character, and with increasing diameter, they become semiconductors because gaps are open by the dimerization of the silicon-silicon distances. Lying at higher energy, we also find that the β SiS monolayer nanotubes are stable with negative strain energy, similar to imogolite nanotubes. The theoretical thermal stability of these two types of silicon monosulfide nanotubes showing such intriguing properties would request further to investigate procedures for their novel synthesis by experimentalists. |
Wednesday, March 17, 2021 5:00PM - 5:12PM Live |
P41.00011: New strategies for submicrometric maskless Additive Manufacturing of metallic structures using Nonlinear Photoreduction Wera Di Cianni, Michele Giocondo, Alberto Sanz de Leon Additive manufacturing (AM) and 3D printing are seen as exciting new industrial production methods fully aligned with the industry 4.0 paradigm. The greatest gamble is placed on their potential use in nanotechnology applications. Direct Laser Writing (DLW) is an example of AM with an ever growing relevance. |
Wednesday, March 17, 2021 5:12PM - 5:24PM Live |
P41.00012: Ghost Coupling: Exact Degeneracies in Guided Modes of Biaxial Dielectric Waveguides Emroz Khan, Sanjay Debnath, Evgenii Narimanov Lifting of degeneracies in a composite system through interaction among its constituents is a generic theme of all physical systems - from splitting of s-orbital energies when two hydrogen atoms are brought nearby to the frequency splitting of propagating modes in optical waveguides. In this work we challenge this well-accepted notion by presenting a new mechanism of mode coupling that does not lift degeneracies. The mechanism is illustrated through the interaction of recently discovered ghost waves (Adv. Photon. 1(4), 046003(2019)), which are a special class of nonuniform electromagnetic waves within biaxial anisotropic materials. The resulting “ghost coupling” offers a fundamentally new way of controlling light-matter interaction with a broad range of potential applications, from integrated waveguides to nonlinear optics and optical sensing. |
Wednesday, March 17, 2021 5:24PM - 5:36PM Live |
P41.00013: Hot-carrier induced giant above-threshold light emission enhancement in plasmonic tunnel junctions Yunxuan Zhu, Longji Cui, Mahdiyeh Abbasi, Arash Ahmadivand, Burak Gerislioglu, Peter Jan Arne Nordlander, Massimiliano Di Ventra, Douglas Natelson Surface plasmon enhanced processes and hot-carrier dynamics in plasmonic nanostructures have attracted much recent interest, revealing distinctive light-matter interactions at the nanoscale. By leveraging plasmonic tunnel junctions as a prototypical platform, recent works have reported enhanced light emission under simultaneous electrical and optical interband excitation at emitted photon energies below threshold (less than applied bias eV or incident photon energy). Here, based on the hot-carrier induced above-threshold electroluminescence, we report a surprising observation of Au nano junctions emitting over 1000-fold more upconverted photons under combined electrical and optical intraband excitation than the simple sum of light emission by either individual stimulus. Analysis of spectra shows that this enhancement is due to dramatic synergistic effects in the generation and interactions of plasmon-induced hot carriers under joint excitations. The observed giant cooperative effect in a plasmonic system may open great potential in on-chip nanophotonic switching, upconversion photovoltaics, and hot-carrier photocatalysis. |
Wednesday, March 17, 2021 5:36PM - 5:48PM Live |
P41.00014: Thermopower of Quantum Wires at the LaAlO3/SrTiO3 Interface Yuhe Tang, Puqing Jiang, Jungwoo Lee, Hyungwoo Lee, Mengchen Huang, Chang-Beom Eom, Patrick R Irvin, Jeremy Levy We report the electrical and thermoelectric transport properties of quantum wires at the LaAlO3/SrTiO3 interface at milli-Kelvin temperatures. A highly enhanced and oscillating thermopower shows up with values exceeding 100 uV/K in the electron depletion regime. The thermopower is correlated with the band structure in the nanowire and well described by the Mott relation. These findings pave the way to study electronic structures of quantum wires at LaAlO3/SrTiO3 with thermal transport technique and can further lead to the understanding of quantization of thermal conductance and other exotic electronic phases in LaAlO3/SrTiO3 systems. |
Wednesday, March 17, 2021 5:48PM - 6:00PM On Demand |
P41.00015: Emergence of winner-takes-all connectivity paths in random nanowire networks Claudia Gomes da Rocha, Elijah Adams, Ciara Chisholm, Thomas Newton, Hugh Manning, Fabio Niosi, Mauro S. Ferreira, John Boland Neuromorphic systems are circuit interconnects designed to emulate the neural processing of a biological brain. Artificial synapses can be reproduced by controlling emergent complex phenomena observed in self-assembly (network) materials exhibiting non-volatile memory in their contact points. When integrated with the proper control systems, these networks can mimic certain brain-functions, e.g. data recognition, and associative memory. We are developing an innovative computational platform designed to model the neuromorphic properties of smart network devices. We demonstrate that networks made of random nanowires are promising architectures for neuromorphic applications due to their connectivity and neurosynaptic-like behaviours. We observed a self-similar scaling of the conductance of networks and the wire-wire junctions that comprise them. These junctions connect by means of a "winner-takes-all" conducting path that spans the entire network, corresponding to the lowest-energy connectivity path. The memory stored in this conductance state is encoded in specific connectivity pathways, similar to that found in biological neuron systems. These results are expected to have important implications for development of neuromorphic devices and reservoir computing. |
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