Ballistic charge transport by mobile nonlinear excitations

The developments in hyperconductivity, the loss-free transmission of electric charge at room temperature and above, due to the ballistic transport of electric charge in crystals with quasi-layered structure, are reported. The electric charge is carried by quodons, a type of mobile nonlinear intrinsic localized mode of lattice excitation observed as fossil tracks in layered silicates and recently by laboratory experiments. Here, ballistic means moving with minimal scattering or interaction with phonons. A test for hyperconductivity in solid materials is developed. It is based on the unique effect of short-term continuation of transport of charge, by total internal reflection, after creation of quodons has ceased. This effect is called the slow-quodon-decay effect or SQD effect. So far, only layered silicates have been shown to exhibit hyperconductivity. New evidence is presented for hyperconductivity in chrysotile, a nonlayered silicate material with new results. Being a fibrous material, it is more flexible than the sheet mica phyllosilicates. It is found that quodons can also be created and carry charge in very different materials, such as polymers, but without showing hyperconductivity, because of the very short range and lifetime of quodons in those materials.Ministerio de Ciencia, Innovación y Universidades PID2019-109175GB-C2

On the charge of quodons

Muscovite mica is a mineral in which the tracks of charged swift particles, from radioactivity or cosmic rays, can be recorded and made visible by decoration with the mineral magnetite. Also, the tracks of quasi-one-dimensional lattice excitations, called quodons, moving along close-packed directions can be recorded. Most quodon tracks evolve from nuclear recoils following decay of the radioactive isotope 40K in mica. The recording process is charge sensitive: moving positive charge precipitates black magnetite and moving negative charge leads to clear epidote. Computer modeling of lattice excitations suggest that breathers or solitons can trap a charge. Most of the decays of 40K leave behind a charge, about 90% of them positive. So the evolution of most quodons from nuclear recoil events occurs in the presence of a charge. The possible energies and mechanisms of charge transmission in the lattice are analyzed. The outcome of 40K decay can be Ca++, Ar0, Ar+ and Ar++. These ions not only have different recoil energy and charge, but also different electron levels and ionization potentials. The first collision of the primary recoiling ion can be inelastic with the transfer of charge to the secondary ion K+. We analyze the possible results taking into account charge, energy and momentum conservation and considering the possible ionization states of the K atoms, which can be intrinsic localized modes, solitons, kinks or crowdions, travelling charge states and combinations of them

Nonlinear waves in a model for silicate layers

Some layered silicates are composed of positive ions, surrounded by layers of ions with opposite sign. Mica muscovite is a particularly interesting material, because there exist fossil and experimental evidence for nonlinear excitations transporting localized energy and charge along the cation rows within the potassium layers. This evidence suggest that there are different kinds of excitations with different energies and properties. Some of the authors proposed recently a one-dimensional model based in physical principles and the silicate structure. The main characteristic of the model is that it has a hard substrate potential and two different repulsion terms, between ions and nuclei. In a previous work with this model, it was found the propagation of crowdions, i.e., lattice kinks in a lattice with substrate potential that transport mass and charge. They have a single specific velocity and energy coherent with the experimental data. In the present work we perform a much more thorough search for nonlinear excitations in the same model using the pseudospectral method to obtain exact nanopteron solutions, which are single kinks with tails, crowdions and bi-crowdions. We analyze their velocities, energies and stability or instability and the possible reasons for the latter. We relate the different excitations with their possible origin from recoils from different beta decays and with the fossil tracks. We explore the consequences of some variation of the physical parameters because their values are not perfectly known. Through a different method, we also have found stationary and moving breathers, that is, localized nonlinear excitations with an internal vibration. Moving breathers have small amplitude and energy, which is also coherent with the fossil evidence.MINECO (Spain) FIS2015-65998-C2-2-PJunta de Andalucía 2017/FQM-280Universidad de Sevilla (España) grants VI PPIT-US-201

Infinite charge mobility in muscovite at 300K

Evidence is presented for infinite charge mobility in natural crystals of muscovite mica at room temperature. Muscovite has a basic layered structure containing a flat monatomic sheet of potassium sandwiched between mirror silicate layers. It is an excellent electrical insulator. Studies of defects in muscovite crystals indicated that positive charge could propagate over great distances along atomic chains in the potassium sheets in absence of an applied electric potential. The charge moved in association with anharmonic lattice excitations that moved at about sonic speed and created by nuclear recoil of the radioactive isotope K40. This was verified by measuring currents passing through crystals when irradiated with energetic alpha particles at room temperature. The charge propagated more than 1000 times the range of the alpha particles of average energy and 250 times the range of channelling particles of maximum energy. The range is limited only by size of the crystal.Comment: 6 pages, 8 figure

Modeling the thermal evolution of enzyme-created bubbles in DNA

The formation of bubbles in nucleic acids (NAs) is fundamental in many biological processes such as DNA replication, recombination, telomere formation and nucleotide excision repair, as well as RNA transcription and splicing. These processes are carried out by assembled complexes with enzymes that separate selected regions of NAs. Within the frame of a nonlinear dynamics approach, we model the structure of the DNA duplex by a nonlinear network of coupled oscillators. We show that, in fact, from certain local structural distortions, there originate oscillating localized patterns, that is, radial and torsional breathers, which are associated with localized H-bond deformations, reminiscent of the replication bubble. We further study the temperature dependence of these oscillating bubbles. To this aim, the underlying nonlinear oscillator network of the DNA duplex is brought into contact with a heat bath using the Nose´–Hoover method. Special attention is paid to the stability of the oscillating bubbles under the imposed thermal perturbations. It is demonstrated that the radial and torsional breathers sustain the impact of thermal perturbations even at temperatures as high as room temperature. Generally, for non-zero temperature, the H-bond breathers move coherently along the double chain, whereas at TZ0 standing radial and torsional breathers result

Pterobreathers in a model for a layered crystal with realistic potentials: Exact moving breathers in a moving frame

In this article we perform a thorough analysis of breathers in a one-dimensional model for a layered silicate for which there exists fossil and experimental evidence of moving excitations along the close-packed lines of the K+ layers. Some of these excitations are likely breathers with a small energy of about 0.2 eV as the numerically obtained breathers described in the present model. Moving breathers as exact solutions of the dynamical equations are obtained at the price of being generically associated with a plane wave, a wing, with finite amplitude, although this amplitude can be very small. We call them pterobreathers. For some frequencies the wings disappear and the solutions become exact moving breathers with no wings, showing the phenomenon of supertransmission of energy. We perform a theoretical analysis of pterobreathers in systems with substrate potential and show that they are characterized by a single frequency in the moving frame plus the frequency of the wings. We have also studied high-energy stationary breathers which transform into single and double kinks and stable multibreathers with very strong localization.Ministerio de Economía y competitividad, FIS2015-65998- C2-2-PMinisterio de Ciencia e Innovación, PRX18/00360Junta de Andalucía, 2017/FQM-280Japan Society for the Promotion of Science, 16K05041Kyoto University Foundation and CASIO Science Promotion Foundation, H29-1

Kinks in Coulomb’s chains

Chains of identical ions, for which the dominant interaction is the electrostatic repulsion, appear in layered silicates. The ions can move almost from site to site. The chains do not explode because the surrounding media has a net negative charge which screens the Coulomb’s repulsion and become attractive when the ions separate two much. Moreover there is a border effect which keeps the ions within the crystal. We have been able to obtain moving supersonic kinks that keep their shape and cross nicely one with each other and can travel over the surrounding sea of phonons. Their energies can be very different, from the order of eVs to hundreds of them. Therefore they can influence many different processes within silicates.Ministerio de Ciencia e Innovación FIS2008-0484

Hyperconductivity in fluorphlogopite at 300 K and 1.1 T

We report on studies of hyperconductivity in which electric charge moves in a solid in the absence of an applied electric field. This is indicative of a non-Ohmic mechanism. Our results are consistent with charge being carried ballistically by mobile nonlinear lattice excitations called quodons moving along close-packed atomic chains in the cation layers of some silicates. The finding that quodons can trap and carry a charge was first found by the authors in muscovite (Russell F. M. et al., EPL, 120 (2017) 46001), which previously was not possible. In this paper we have also found hyperconductivity in lepidolite, phlogopite and synthetic fluorphlogopite but not in biotite or quartz. We have found that a current continues to flow for many seconds after the creation of quodons is stopped, indicating they have long flight-paths. This shows that quodons are decoupled from phonons, must experience elastic reflection at boundaries and are not stopped by inevitable dislocations or other minor defects. We have also found that quodons can anneal defects caused by mechanical working of crystal faces. The current carried by quodons is unaffected by a magnetic field of 1.1 T.Ministerio de Ciencia e Innovación, PRX18/00360Ministerio de Economía y competitividad, FIS2015-65998- C2-2-PJunta de Andalucía, 2017/FQM-28

Effect of breather existence on reconstructive transformations in mica muscovite

The International Workshop on Complex Systems (5º. 2007. Sendai, Japan)Reconstructive transformations of layered silicates as mica muscovite take place at much lower temperatures than expected. A possible explanation is the existence of breathers within the potassium layer. Numerical analysis of a model shows the existence of many different types of breathers with different energies and existence ranges which spectrum coincides approximately with a statistical theory for them.Ministerio de Educacion y Ciencia, Spain, project FIS2004-0118