Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session G66: Novel TechniquesRecordings Available

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Chair: Timothy Kidd, INI Room: Hyatt Regency Hotel Grant Park D 
Tuesday, March 15, 2022 11:30AM  11:42AM 
G66.00001: Physical properties of the nanopore ion source Nicholas Drachman, Derek M Stein Mass spectrometry (MS) is a vital technique for biological and chemical analysis due in large part to the availability of soft ionization techniques such as electrospray ionization (ESI), which can transfer molecular ions into the gas phase without damaging them. However, the ESI process utilizes a background gas which degrades ion transmission, resulting in analyte ion transmission efficiencies of around 1%, limiting the sensitivity of MS. We have developed a nanopore ion source which can deliver ions directly into high vacuum from aqueous solutions with high efficiency. The heart of the ion source is a pulled quartz capillary with a tip diameter of less than 100 nm. Surface tension at the nanoscale liquidvacuum interface can maintain a stable meniscus with high charge density, enabling electric fields on the order of 1 V/nm to be reached. At such high fields, ions can be emitted from the meniscus by ion evaporation without the emission of liquid droplets as in conventional electrospray. We discuss potential applications for the nanopore ion source, notably in increasing MS sensitivity and enabling single molecule protein sequencing. 
Tuesday, March 15, 2022 11:42AM  11:54AM 
G66.00002: Matrixpairing states in the alkaline Feselenide superconductors: exotic Josephson junctions Emilian M Nica, Qimiao Si, Onur Erten Multiband alkaline Feselenides and the heavyfermion CeCu_{2}Si_{2} show signatures of fullygapped but signchanging superconductivity. A twoorbital pairing state, called sτ_{3}, with nontrivial matrix structure, was proposed to reconcile the seemingly contradictory properties of these superconductors. Motivated by the orbitalselective pairing structure, we study prototypical Josephson junctions where at least one of the leads is in a superconducting state of this kind. The limit of two degenerate orbitals reveals two remarkable properties. One is the emergence of gapless bound states which are purely electron and holelike in the N part, and which persist under arbitrary global phase differences for sτ_{3}Nsτ_{3 }junctions. The other is the absence of static Josephson currents when both leads are superconducting. In these aspects, sτ_{3 }junctions are significantly different from conventional Josephson junctions. We find that the gapless bound states are protected by an orbitalexchange symmetry, although the protection is not topological. Junctions which break this symmetry, such as sτ_{3}Ns, have gapped Andreev bound states. The Josephson effect reemerges once the degeneracy of the two orbitals is lifted. Our results indicate that junctions involving sτ_{3} pairing in alkaline Feselenides will generically have bound states with a small gap and a greatly suppressed Josephson current. 
Tuesday, March 15, 2022 11:54AM  12:06PM 
G66.00003: Bioinspired Space Filling Fractal Network Metamaterial Tiantian Li, Yaning Li Fractal geometry are prevalent in natural composite materials. Inspired by the complex fractal geometry of deer cranial suture, we introduced the mathematical concept of spacefilling fractal curves to describe the pattern formed by a continuously moving point in space. Two spacefilling curves, Hillbert and Peano curves, are used to design twophase mechanical metamaterials. The designs are fabricated via a multimaterial 3D printer. Along the spacefilling lines, soft rubbery material is used, forming a connected compliant layer to provide constrains for the second phase. Outside the soft phase, a hard plastic material is used as the second phase. Mechanical experiments under uniaxial tension are conducted on the specimens. The effect of fractal iteration and the volume fraction of the two phases are systematically quantified. Both analytical and numerical analyses are performed to predict the effective material properties. 
Tuesday, March 15, 2022 12:06PM  12:18PM 
G66.00004: Exploring the Consequences of NonHermiticity and PT Symmetry in Electronic Transport Joseph Soruco In recent years, nonHermitian Hamiltonians and their exceptional point (EP) degeneracies have been heavily explored in classical and quantum systems. Coherent electronic transport occurring within a sample material connected to leads is usually described in terms of momentumdependent, nonHermitian selfenergy operator. And yet, EPs and their consequences in such transport are unexplored. Using a tightbinding model for a spinpreserving sample and spinmixing contacts connected to leads, we explore the consequences of nonHermitian Hamiltonian in the spinspace on coherent electronic transport. In particular, we determine the behavior of the electrical conductance near the exceptional points. Our theoretical calculations provide a framework to understand the role of nonHermiticity, beyond global dissipation, in simple condensed matter systems. 
Tuesday, March 15, 2022 12:18PM  12:30PM 
G66.00005: Efficient GW calculations in two dimensional through the interpolation of the screened potential Alberto Guandalini, Pino D'Amico, Andrea Ferretti, Daniele Varsano The GW selfenergy approximation is able to accurately predict quasiparticle (QP) properties of several classes of materials. However, the calculation of the QP band structure of 2D semiconductors is challenging due to the sharp qdependence of the dielectric function in the longwavelength limit (q→0). In this case, a very dense qsampling of the Brillouin zone is usually needed to obtain properly converged quantities. In this work, we assess the possibility to drastically improve the convergence of the QP corrections of 2D semiconductors with respect to the qsampling, by combining Monte Carlo integration techniques and interpolation schemes of the screened potential. 
Tuesday, March 15, 2022 12:30PM  12:42PM 
G66.00006: A new generation of effective core potentials from correlated and spinorbit calculations: selected heavy elements Benjamin E Kincaid, Guangming Wang, Haihan Zhou, Abdulgani Annaberdiyev, Michael C Bennett, Jaron T Krogel, Lubos Mitas We generate new correlation consistent effective core potentials (ccECPs) for the elements I, Bi, Ag, Au, Pd, Ir, Mo, Te and W with 4d, 5d, 6s and 6p valence spaces. These ccECPs are given as a sum of averaged spinorbit (AREP) and effective spinorbit (SO) terms. The construction involves several steps with increasing refinements in corresponding calculations of allelectron atoms using Coupled Cluster methods and optimizations of objective functions that include weighted atomic spectra, normconservations, spinorbit effects and molecular binding curves for hydride and oxide dimers. The constructed ccECPs provide a consistent accuracy for valenceonly calculations for these elements with significant improvements compared to previous tables. Our study confirms the importance of the AREP part in determining the overall accuracy in subsequent calculations such as trial wave functions in quantum Monte Carlo calculations. 
Tuesday, March 15, 2022 12:42PM  12:54PM 
G66.00007: Magnetoexcitons in phosphorene monolayer, bilayer, and van der Waals heterostructure Anastasia Spiridonova, Roman Y Kezerashvili We study direct and indirect magnetoexcitons in Rydberg states in phosphorene monolayers, bilayer, and van der Waals heterostructure in an external magnetic field applied perpendicular to the monolayer or heterostructure within the framework of the effective mass approximation. Binding energies of magnetoexcitons are calculated by numerical integration of the Schrödinger equation using the RytovaKeldysh potential for direct magnetoexcitons and both the RytovaKeldysh and Coulomb potentials for indirect one. We report the magnetic field energy contribution to the binding energies and diamagnetic coefficients (DMCs) for magnetoexcitons and show their strong depends on the effective masses of electron and hole. We demonstrate theoretically that phosphorene is a novel category of 2D semiconductors offering a tunability of the binding energies of magnetoexcitons by means of external magnetic field and control of the binding energies and DMCs by the number of hBN layers separating two phosphorene sheets. Such tunability is potentially useful for the design of the device. 
Tuesday, March 15, 2022 12:54PM  1:06PM 
G66.00008: Quantization of Protons in Periodic Electronic Structure Calculation Jianhang Xu, Ruiyi Zhou, Zhen Tao, Christopher Malbon, Volker Blum, Sharon HammesSchiffer, Yosuke Kanai The nuclearelectronic orbital (NEO) method is a wellestablished approach for treating nuclei quantum mechanically in molecular systems beyond the usual BornOppenheimer approximation. In this work, we present a new strategy to implement the NEO method into periodic electronic structure calculations, particularly focused on density functional theory calculations. We discuss our implementation in an allelectron electronic structure code, FHIaims, and show agreement with an existing NEO implementation for molecular systems in the QChem code. Proofofconcept examples are presented to illustrate the effects of quantized protons on the electronic structures of extended systems such as 2D materials and liquidsemiconductor interfaces. In addition to the proton quantization effects for the extended systems, our work shows that the electronproton correlation has a nonnegligible impact on band structures. 
Tuesday, March 15, 2022 1:06PM  1:18PM 
G66.00009: Relativistic DouglasKrollHess Calculations of Hyperfine Interactions within First Principles Multireference Methods Aleksander L Wysocki, Kyungwha Park Hyperfine interaction plays a crucial role in understanding EPR and NMR spectra of materials, provides an important source of decoherence for electronic spins, and enables an external control of nuclear spin qubits in quantum information devices. We present an ab initio method for calculations of relativistic hyperfine coupling parameters using multireference quantum chemistry techniques. The relativistic treatment is based on the second order DouglasKrollHess (DKH) theory. The method is implemented in the Molcas/OpenMolcas package. The implementation is first tested for atoms, ions, and simple molecules. The results are compared with experiment and other calculations. The effects of relativistic correction, finite nuclei size, core polarization, and dynamic correlations are discussed. Next, we consider hyperfine coupling for singlemolecule magnets (SMM)s. Our implementation allows for calculations even for large molecules like TbPc_{2} with a wellconverged basis. We demonstrate that the relativistic treatment of hyperfine coupling is crucial for SMMs with strong Fermi contact contribution like TbCp_{2} molecule with a divalent Tb ion. Finally, we study the electric field dependence of hyperfine interaction in SMMs. 
Tuesday, March 15, 2022 1:18PM  1:30PM 
G66.00010: Chaos in a timeperiodically modulated honeycomb optical lattice Walter A Furman, Aaron D Barr, Linda E Reichl, Max D Porter Rubidium atom currents in a timeperiodically modulated honeycomb optical lattice are numerically computed. This modulation acts as a driving that leads to chaotic behavior in the atom dynamics. We treat this system both classically — showing the onset of chaos in lattice surfaceofsection plots — and quantum mechanically — using FloquetBloch theory to compute the quasienergy and average energy spectrum, as well as the atomic currents induced by the modulation. The distribution of quasienergies suggest the signatures of chaos arise as the modulation amplitude increases. 
Tuesday, March 15, 2022 1:30PM  1:42PM 
G66.00011: Directional anomalous skin effect in PdCoO_{2} Graham Baker, Timothy Branch, James Day, Philippa H McGuinness, Seunghyun Khim, Mohamed Oudah, Davide Valentinis, Roderich Moessner, Joerg Schmalian, Andrew Mackenzie, Douglas A Bonn The delafossite metal PdCoO_{2} is notable for its exceptionally long lowtemperature mean free path (MFP) and simple, nearlyhexagonal Fermi surface [1]. Recent measurements of DC transport in widthrestricted channels of PdCoO_{2} found that in the ballistic regime—in which the MFP is longer than the channel width—the stronglyfaceted Fermi surface results in a large resistivity anisotropy that is symmetryforbidden in the bulk limit, demonstrating the notion of “directional ballistics” [2]. In AC electrodynamics, current is intrinsically confined to a narrow layer, even in an infinite sample, because of the skin effect. Analogous to the ballistic regime, the anomalous skin effect occurs when the MFP is longer than the skin depth. Here we present microwave spectroscopy measurements of PdCoO_{2} in two geometries which would be symmetryequivalent for local electrodynamics. Instead, the two measurements differ strongly in magnitude and frequency dependence. By comparing our measurements to Boltzmann calculations, we show that the stronglyfaceted Fermi surface of PdCoO_{2} gives rise to a directional anomalous skin effect. 
Tuesday, March 15, 2022 1:42PM  1:54PM 
G66.00012: Thin Film Silica Aerogel Structures for Heavy Ion Particle Detectors and Applications to Superfluid ^{3}He William P Halperin, YunChieh Tsai, Man D Nguyen, John W Scott We investigate the use of high porosity silica (SiO_{2}) aerogel as a particle filter in heavy ion detectors to discriminate between electrons and positive ions. Our prototype device consists of silica aerogel grown in stainless steel 25µ micromesh that is designed to optimize electron transmission while absorbing positive ions. The samples are produced by the supercritical drying of alcogel (SiO_{2} matrix suspended in methanol) imbibed in the micromesh, producing aerogel that fills the holes of the mesh. We then characterize the aerogelfilled mesh for homogeneity and electronic transparency using scanning electron and transmission electron microscopy (SEM and TEM). SEM analysis indicates that aerogel fills the mesh holes. TEM analysis indicates that electron transmission through aerogelfilled mesh holes is approximately half that of transmission through empty mesh holes. Other applications of this new technology include stabilization of superfluid phases of 3He and potentially their superfluidnormalsuperfluid coherent structures. 
Tuesday, March 15, 2022 1:54PM  2:06PM 
G66.00013: Model and analysis of 2D SQUID arrays at 77 K: Study of the magnetic field response and coupling radius Marc Gali Labarias, KarlHeinz Muller, Emma Mitchell Superconducting quantum interference device (SQUID) arrays have been widely investigated to extend the functionality of a single SQUID. Despite the existence of models for SQUID arrays at lowtemperatures, these models fail to correctly predict the response of arrays operating at higher temperatures, as is the case for hightemperature materials at 77K. 
Tuesday, March 15, 2022 2:06PM  2:18PM 
G66.00014: Additivefree Gelation of Graphene Oxide Dispersion Induced by Mild Thermal Annealing Geon Woong Kim, So Youn Kim Graphene oxide (GO) exhibits good dispersibility and colloidal stability in an aqueous solution based on its functional groups on the basal plane and edges. These properties enable solution processing of GO for various forms of GObased products such as fiber, membrane, aerogel, etc. In the processing of these applications, GO dispersions often require a proper phase transition to gel to have sufficient modulus. Conventionally, the gelation of GO dispersion occurs through the addition of polymer or salt; however, these additives act as impurities that can decrease the GO dispersibility and lower the electrical properties of the final product. 
Tuesday, March 15, 2022 2:18PM  2:30PM 
G66.00015: Spontaneous generation and propagation capabilities as pseudoembedded but stochastically communication and intelligence like mechanisms in complex exotic molecular chains: CIinCEMCs Taner Şengör The electromagnetically equivalence processes, EEPs relevant to worldwide spreadable diseases manifolds, DMs are designed. The EEPS are determined for both natural generation processes, NgPs of exotic viruses, EVs and their spontaneous, SP propagation capabilities as pseudoembedded but stochastically SP communication and intelligence like mechanisms in complex exotic molecular chains. Approach is related to studies connecting viruslike but nonvirotic structures, virutics going to be a virus with a stochastically electromagnetic, EM initial boundary value problem, SEMIBVP. The EEP is formulated for both EM events and EVs from studies of inflective spaces and waves. Recent pandemic has topology relatable to first stage of worldwide spreading exotic DM. EEPs for NgPs are designed and equivalent specifications of behavior of novel virus are given as wave phenomenon. Selfbuilding mechanism for both novel and future EVs is designed. Possible triggers of EV creation are explained with a SEMIBVP process. Multi effect mechanisms coming from significant EM radiation density in atmosphere and the simplest particles at upper bound of atmosphere, outer space, and earth are explained in SEMIBVP of significant NgPs beginning from early 2000 going to 20382040 by accelerating until 2028. 
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