The tunneling characteristics of planar junctions between a normal metal and a non-centrosymmetric superconductor like CePt3Si are examined. It is shown that the superconducting phase with mixed parity can give rise to characteristic zero-bias anomalies in certain junction directions. The origin of these zero-bias anomalies are Andreev bound states at the interface. The tunneling characteristics for different directions allow to test the structure of the parity-mixed pairing state.

Josephson effect in junctions between unconventional superconductors is studied theoretically within the model describing the effects of interface roughness. The particularly important issue of applicability of the frequently used Sigrist-Rice ͑SR͒ formula for Josephson current in d-wave superconductor/insulator/d-wave superconductor junctions is addressed. We show that although the SR formula is not applicable in the ballistic case, it works well for rough interfaces when the diffusive normal metal regions exist between the d-wave superconductor and the insulator. It is shown that the SR approach only takes into account the component of the d-wave pair potential symmetric with respect to an inversion around the plane perpendicular to the interface. Similar formula can be derived for general unconventional superconductors with arbitrary angular momentum l. [1][2][3][4] Because of such unconventional symmetry, the study of Josephson effect in high-T C superconducting ͑HTS͒ junctions attracted a lot of interest. A while ago, a simple formula for the Josephson current of d-wave superconductor/insulator/d-wave superconductor ͑DID͒ junctions was proposed by Sigrist and Rice ͑SR͒. 5 According to the SR formula, the Josephson current is proportional to cos 2␣ cos 2␤, where the ␣͑␤͒ denotes the angle between the normal to the interface and the crystal axis of the left͑right͒ d-wave superconductor. 5 Although the SR formula can explain experiments with the so-called junctions, 1,2 this formula does not take into account the effect of midgap Andreev resonant states ͑MARS͒ formed at junction interfaces. 6,7 Actually, as shown in Ref. 8, SR formula does not work in ballistic d-wave junctions for ␣ 0 and ␤ 0 where MARS influence severely the charge transport at low temperatures. It was shown both theoretically 9,10 and experimentally 11,12 that MARS induce a nonmonotonic temperature dependence of the maximum Josephson current in DID junctions. On the other hand, SR formula has been extensively used to analyze experiments with various types of HTS Josephson junctions. [13][14][15] Experiments with HTS junctions are of high importance for basic understanding of high-T c superconductivity since they may provide information on possible subdominant admixtures to the d-wave symmetry. [16][17][18] Therefore it is of fundamental interest to understand the physical mechanisms that determine the angular dependence of Josephson current in HTS junctions. For this reason, the determination of the conditions of applicability of the SR formula is an important issue which is addressed in the present paper.In the following, we study the Josephson current in D /DN/I /DN/D junctions, where DN denotes diffusive normal metal and could be formed between the insulator and d-wave superconductors. The calculations are based on the quasiclassical Green's function method applicable to unconventional superconductor junctions. 19,20 We find that the resulting Josephson current in D /DN/I /DN/D junctions is well fitted by the SR formula. Near the transi...

We study Josephson current in superconductor/diffusive ferromagnet/superconductor junctions by using the recursive Green function method. When the exchange potential in a ferromagnet is sufficiently large compared to the pair potential in a superconductor, an ensemble average of Josephson current is much smaller than its mesoscopic fluctuations. The Josephson current vanishes when the exchange potential is extremely large so that a ferromagnet is half-metallic. Spin-flip scattering at junction interfaces drastically changes the characteristic behavior of Josephson current. In addition to spin-singlet Cooper pairs, equal-spin triplet pairs penetrate into a half metal. Such equal-spin pairs have an unusual symmetry property called odd-frequency symmetry and carry the Josephson current through a half metal. The penetration of odd-frequency pairs into a half metal enhances the low energy quasiparticle density of states, which could be detected experimentally by scanning tunneling spectroscopy. We will also show that odd-frequency pairs in a half metal cause a nonmonotonic temperature dependence of the critical Josephson current.

Functional polymeric materials constructed by noncovalent bonds have attracted considerable attention due to their beneficial stretching and self-healing properties. We chose host−guest interactions using cyclodextrins (CDs) as host molecules to realize supramolecular materials with stretching and self-healing properties. Notably, an inclusion complex of a CD and a guest molecule functions as a reversible bond in a material. Herein, we studied the relationship between the mechanical properties of the materials and host−guest interactions based on the association constants of CDs with guest molecules and molecular structures of the guest molecules. A chemically cross-linked poly(acrylamide) gel showed high rupture stress, although the rupture strain was noticeably low. However, the host−guest hydrogels (CDAAmMe-R hydrogels) exhibited a higher rupture stress and strain of approximately 1000%. These rupture stress and strain values were related to the association constants of the CDs with guest units on the polymer side chain and the structure of the guest molecules. In particular, the αCDAAmMe-Dod hydrogel with a dodecyl group with a long, rod-like structure showed better rupture stress and strain (1250%). The βCDAAmMe-AdAAm hydrogel with a spherical adamantyl acrylamide (AdAAm) group showed better self-healing properties. To realize a practical self-healing process under dry conditions, a poly(methyl triethylene glycol acrylate) xerogels with βCDAAmMe and AdAAm (βCDAAmMe-AdAAm TEGA xerogel) was prepared. The βCDAAmMe-AdAAm TEGA xerogel exhibited selfhealing properties, regaining 61% of its initial material strength at 100 °C.

[1] The atmospheric N 2 O variations between the Earth's surface and the lower stratosphere, simulated by an atmospheric general circulation model-based chemistry transport model (ACTM), are compared with aircraft and satellite observations. We validate the newly developed ACTM simulations of N 2 O for loss rate and transport in the stratosphere using satellite observations from the Aura Microwave Limb Sounder (Aura-MLS), with optimized surface fluxes for reproducing N 2 O trends observed at the surface stations. Observations in the upper troposphere/lower stratosphere (UT/LS) obtained by the Japan AirLines commercial flights commuting between Narita (36°N), Japan, and Sydney (34°S), Australia, have been used to study the role of stratospheretroposphere exchange (STE) on N 2 O variability near the tropopause. Low N 2 O concentration events in the UT region are shown to be captured statistically significantly by the ACTM simulation. This is attributed to successful reproduction of stratospheric air intrusion events and N 2 O vertical/horizontal gradients in the lower stratosphere. The meteorological fields and N 2 O concentrations reproduced in the ACTM are used to illustrate the mechanisms of STE and subsequent downward propagation of N 2 O-depleted stratospheric air in the troposphere. Aircraft observations of N 2 O vertical profile over Surgut (West Siberia, Russia; 61°N), Sendai-Fukuoka (Japan; 34°N-38°N), and Cape Grim (Tasmania, Australia; 41°S) have been used to estimate the relative contribution of surface fluxes, transport seasonality in the troposphere, and STE to N 2 O seasonal cycles at different altitude levels. Stratospheric N 2 O tracers are incorporated in the ACTM for quantitative estimation of the stratospheric influence on tropospheric N 2 O. The results suggest strong latitude dependency of the stratospheric contribution to the tropospheric N 2 O seasonal cycle. The periods of seasonal minimum in the upper troposphere, which are spring over Japan and summer over Surgut, are in good agreement between the ACTM and observation and indicate a different propagation path of the stratospheric signal between the two sites in the Northern Hemisphere. The stratospheric tracer simulations, when utilized with the observed seasonal cycle, also provide qualitative information on the seasonal variation in surface fluxes of N 2 O.Citation: Ishijima, K., et al. (2010), Stratospheric influence on the seasonal cycle of nitrous oxide in the troposphere as deduced from aircraft observations and model simulations,