Liquid/solid interfaces are attracting growing interest not only for applications in catalytic activities and energy storage, but also for their new electronic functions in electric double-layer transistors (EDLTs) exemplified by high-performance organic electronics, field-induced electronic phase transitions, as well as superconductivity in SrTiO(3) (ref. 12). Broadening EDLTs to induce superconductivity within other materials is highly demanded for enriching the materials science of superconductors. However, it is severely hampered by inadequate choice of materials and processing techniques. Here we introduce an easy method using ionic liquids as gate dielectrics, mechanical micro-cleavage techniques for surface preparation, and report the observation of field-induced superconductivity showing a transition temperature T(c)=15.2 K on an atomically flat film of layered nitride compound, ZrNCl. The present result reveals that the EDLT is an extremely versatile tool to induce electronic phase transitions by electrostatic charge accumulation and provides new routes in the search for superconductors beyond those synthesized by traditional chemical methods.

If it is observed only a function of the state in a finite-state Markov chain, then the stochastic process is no longer Markovian in general. This type of information source is found widely and the basic problem of their identifiability has remained open, that is, the problem of showing when two different Markov chains generate the same stochastic process. The identifiability problem is completely solved by linear algebra, where a block structure of a Markov transition matrix plays a fundamental role, and from which the minimum degree of freedom for a source is revealed.Index Terms-Function process, hidden Markov, identifiability problem, minimum degree of freedom.

The doping dependence of specific heat and magnetic susceptibility has been investigated for Li(x)ZrNCl superconductors derived from a band insulator. As the carrier concentration is decreased, the anisotropy of superconducting gap changes from highly anisotropic to almost isotropic. It was also found that, upon reducing carrier density, the superconducting coupling strength and the magnetic susceptibility are concomitantly enhanced in parallel with T(c), while the density of states at the Fermi level is kept almost constant. Theoretical calculations taking into account the on-site Coulomb interaction reproduced the experimental results, suggesting a possible pairing mediated by magnetic fluctuations, even in the doped band insulators.

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Abstruct-A new achievable rate region for the general interferencechannel which extends previous results is presented and evaluated. Tbe technique used is a generalization of superposition coding to the multivariable case. A detailed computation for tbe Gaussian cbaunel case clarifies to wbat extent the new region improves previous ones. The capacity of a class of Gaussian interference channels is also established.

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