Mixed spin-singlet and spin-triplet pairing can occur in noncentrosymmetric superconductors. In this respect, a comprehensive characterization of the noncentrosymmetric superconductor BeAu was carried out. It was established that BeAu undergoes a structural phase transition from a low-temperature noncentrosymmetric FeSi structure type to a high-temperature centrosymmetric structure in the CsCl type at T-s = 860 K. The low-temperature modification exhibits a superconducting transition below T-c = 3.3 K. The values of lower (H-c1 = 32 Oe) and upper (H-c2 = 335 Oe) critical fields are rather small, confirming that this type-II (kappa(G-L) = 2.3) weakly coupled (lambda(e-p) = 0.5, Delta C-e/gamma T-n(c) approximate to 1.26) superconductor can be well understood within the Bardeen-Cooper-Schrieffer theory. The muon spin relaxation analysis indicates that the time-reversal symmetry is preserved when the superconducting state is entered, supporting conventional superconductivity in BeAu. From the density functional band structure calculations, a considerable contribution of the Be electrons to the superconducting state was established. On average, a rather small mass renormalization was found, consistent with the experimental data

Precise measurements of the thermodynamic critical field (Bc) in type-I noncentrosymmetric superconductor BeAu were performed by means of the muon-spin rotation/relaxation technique. The temperature evolution of Bc can not be described within the single gap scenario and it requires the presence of at least two different types of the superconducting order parameters. The selfconsistent two-gap approach, adapted for analysis of Bc(T ) behavior, suggests the presence of two superconducing energy gaps with the gap to Tc ratios 2∆/kBTc 4.52 and 2.37 for the big and the small gap, respectively. This implies that the superconductivity in BeAu is unconventional and that the supercarrier pairing occurs at various energy bands.BeAu is an old known superconductor with the transition temperature T c 3.2 K. Superconductivity in BeAu was originally discovered by Matthias in 1959, 1 i.e. just in two years after the formulation of the BCS theory. 2 In this short report, Matthias was noted the absence of a superconductivity in a pure Be and Au (Be was later found to have T c 26 mK, Ref.3) and performed a search within the gold-rich site of the Be-Au phase diagram. The superconductivity was found to appear in a stoichiometric (i.e. 1:1 Be to Au ratio) BeAu sample. 1Recently, the interest to BeAu was renewed. [4][5][6][7][8] This mostly relates to the realisation of their noncentrosymmetric crystal structure, which was expected to give rise to unconventional superconductivity due to spin-orbit coupling and/or mixed singlet/triplet pairing state (see e.g. Refs. 9-16 and references therein). In addition, the B20 FeSi-type of the crystal structure of BeAu becomes particualry interesting since such materials were predicted to host chiral fermions in topological semimetals. [17][18][19] Moreover, B20 structure is the only known crystal structure for bulk magnetic skyrmions in materials such as MnSi, Fe 1−x Co x Si, FeGe, MnGe, Cu 2 OSeO 3 etc. [20][21][22][23][24] All these make BeAu an intriguing candidate material to search for unconventional superconductivity, associated with its noncentrosymmetric crystal structure in combination with the possible existence of exotic quasiparticles.

In search of the origin of superconductivity (SC) in diluted rhenium superconductors and their significantly enhanced T c compared to pure Be (0.026 K), we investigated the intermetallic ReBe 22 compound, mostly by means of muon-spin rotation/relaxation (μSR). At a macroscopic level, its bulk SC (with T c =9.4 K) was studied via electrical resistivity, magnetization, and heat-capacity measurements. The superfluid density, as determined from transverse-field μSR and electronic specific-heat measurements, suggest that ReBe 22 is a fully-gapped superconductor with some multigap features. The larger gap value, D = 1.78 l 0 T k B c , with a weight of almost 90%, is slightly higher than that expected from the BCS theory in the weak-coupling case. The multigap feature, rather unusual for an almost elemental superconductor, is further supported by the field-dependent specific-heat coefficient, the temperature dependence of the upper critical field, as well as by electronic bandstructure calculations. The absence of spontaneous magnetic fields below T c , as determined from zero-field μSR measurements, indicates a preserved time-reversal symmetry in the superconducting state of ReBe 22 . In general, we find that a dramatic increase in the density of states at the Fermi level and an increase in the electron-phonon coupling strength, both contribute to the highly enhanced T c value of ReBe 22 .

The recent discovery of a low-temperature endotherm upon heating hydrochloric-acid doped ice VI has sparked a vivid controversy. The two competing explanations aiming to explain its origin range from a new distinct crystalline phase of ice to deep-glassy states of the well-known ice VI.Problems with the slow kinetics of deuterated phases have been raised, which we circumvent here entirely by simultaneously measuring the inelastic neutron spectra and neutron diffraction data of H2O samples. These measurements clearly confirm the deep-glassy ice VI scenario and rule out alternative explanations. Additionally, we show that the crystallographic model of D2O ice XV, the ordered counterpart of ice VI, also applies to the corresponding H2O phase. The discovery of deep-glassy ice VI now provides a fascinating new example of ultra-stable glasses which are encountered across a wide range of other materials. TOC GRAPHICS

Semiconducting substances form one of the most important families of functional materials. However, semiconductors containing only metals are very rare. The chemical mechanisms behind their ground‐state properties are only partially understood. Our investigations have rather unexpectedly revealed the semiconducting behaviour (band gap of 190 meV) for the intermetallic compound Be5Pt formed at a very low valence‐electron count. Quantum‐chemical analysis shows strong charge transfer from Be to Pt and reveals a three‐dimensional entity of vertex‐condensed empty Be4 tetrahedrons with multi‐atomic cluster bonds interpenetrated by the framework of Pt‐filled vertex‐condensed Be4 tetrahedrons with two‐atomic polar Be−Pt bonds. The combination of strong Coulomb interactions with relativistic effects results in a band gap.

GeneralThe SCTE 2018 will follow a series of conferences, dating back more than 50 years, with recent meetings in Annecy, France, (2010), Lisboa, Portugal (2012), Genova, Italy, (2014) and Zaragossa, Spain (2016). The SCTE has always been a forum, where new ideas and discoveries -related to the solid state chemistry and solid state physics of d-and f-element compounds -are presented and discussed.The conference will deal with the structure, crystal chemistry, chemical bonding, and magnetic and electronic transport properties of different classes of intermetallic compounds. The field of hydrides, borides, carbides, silicides and homologues, pnictides, as well as chalcogenides, oxides and halides (especially those of low oxidation state exhibiting metal or semimetal properties) will also be covered.Fundamental and applied research in the areas of solid state chemistry, physics and materials science of compounds containing d-and f-elements will be included. Conference SiteThe conference will be held in the Institute building "Freihaus" of the Technische Universität Wien, using the lecture rooms V and VI. The poster session will also be held in the "Freihaus", Wiedner Hauptstrasse 8-10, 1040 Wien (see the campus map). Technische Universität Wien is located in the city center of Vienna, thus conveniently accessible by the Vienna public transport system. The nearest station to the conference site is "Karlsplatz", to where the underground-lines U1, U2 and U4 are bound. Additionally, the tramway lines 62, 65 as well as 1, 2, D, J, Bus 4 and "Badner Bahn" are nearby. Parking slots for private cars are available in a public park house within the conference building (about A C 90.-/week and A C 4.-/hour). CurrencyThe offcial currency in Austria is the EURO (A C). Foreign currencies can be exchanged in Euro in all banks. The airport and most railway stations have exchange desks and money is available in numerous cash dispensers, prepared for major international cards. Hotels, restaurants, and many shops and travel agencies accept credit cards.iii Language The conference language is English. The language of Austria is German. Conference FeesEarly bird rate:A C 390. • Admission to all technical sessions• Conference material, including the book of abstracts• One printed version of the conference proceedings (students and retirees will not receive the printed versions of the conference proceedings)• Daily coffee breaks• Welcome reception on Sunday, March 25, 2018• Conference dinner on Wednesday, March 28, 2018Accompanying person's conference fees include:• Welcome reception on Sunday, March 25, 2018• Conference dinner on Wednesday, March 28, 2018• Daily coffee breaks• Two guided tours in Vienna Note:• All participants must register with full remittance• Payment after March 15, 2018 is only possible at the conference site (in cash, Euros). RegistrationOn-site registration at the conference will open on Sunday, March 25, 2018 at 15:00 . All conference participants, including speakers, must register at the conference and will re...

We present muon spin rotation and relaxation (µSR) measurements as well as demagnetising field corrected magnetisation measurements on polycrystalline samples of the noncentrosymmetric superconductor BeAu. From µSR measurements in a transverse field, we determine that BeAu is a type-I superconductor with Hc = 256 Oe, amending the previous understanding of the compound as a type-II superconductor. To account for demagnetising effects in magnetisation measurements, we produce an ellipsoidal sample, for which a demagnetisation factor can be calculated. After correcting for demagnetising effects, our magnetisation results are in agreement with our µSR measurements. Using both types of measurements we construct a phase diagram from T = 30 mK to Tc ≈ 3.25 K. We then study the effect of hydrostatic pressure and find that 450 MPa decreases Tc by 34 mK, comparable to the change seen in type-I elemental superconductors Sn, In and Ta, suggesting BeAu is far from a quantum critical point accessible by the application of pressure. arXiv:1902.00073v1 [cond-mat.supr-con]

Amorphous ices govern a range of cosmological processes and are potentially key materials for explaining the anomalies of liquid water. A substantial density gap between low-density and high-density amorphous ice with liquid water in the middle is a cornerstone of our current understanding of water. However, we show that ball milling “ordinary” ice I h at low temperature gives a structurally distinct medium-density amorphous ice (MDA) within this density gap. These results raise the possibility that MDA is the true glassy state of liquid water or alternatively a heavily sheared crystalline state. Notably, the compression of MDA at low temperature leads to a sharp increase of its recrystallization enthalpy, highlighting that H 2 O can be a high-energy geophysical material.