581 research outputs found
2-(o-Tolyloxy)benzoic acid
In the crystal structure of the title compound, C14H12O3, molecules are linked via intermolecular O—H⋯O hydrogen bonds, resulting in dimer formation. The dihedral angle between the two phenyl rings is 76.2 (2)°
Superconductivity Induced by Site-Selective Arsenic Doping in MoSi
Arsenic doping in silicides has been much less studied compared with
phosphorus. In this study, superconductivity is successfully induced by As
doping in MoSi. The superconducting transition temperature ()
reaches 7.7 K, which is higher than those in previously known WSi-type
superconductors. MoSiAs is a type-II BCS superconductor with upper and
lower critical fields of 6.65 T and 22.4 mT, respectively. In addition, As
atoms are found to selectively take the 8 sites in MoSiAs. The
emergence of superconductivity is possibly due to the shift of Fermi level as a
consequence of As doping, as revealed by the specific heat measurements and
first-principles calculations. Our work provides not only another example of As
doping, but also a practical strategy to achieve superconductivity in silicides
through Fermi level engineering.Comment: Supporting Information available at the corresponding DO
Strong-Coupling Superconductivity with 10.8 K Induced by P Doping in the Topological Semimetal MoSi
By performing P doping on the Si sites in the topological semimetal
MoSi, we discover strong-coupling superconductivity in
MoSiP (0.5 2.0). MoSi crystallizes in
the WSi-type structure with space group of (No. 140), and is
not a superconductor itself. Upon P doping, the lattice parameter decreases
while increases monotonously. Bulk superconductivity is revealed in
MoSiP (0.5 2.0) from resistivity,
magnetization, and heat capacity measurements. in
MoSiP reaches as high as 10.8 K, setting a new record among
the WSi-type superconductors. The upper and lower critical fields for
MoSiP are 14.56 T and 105 mT, respectively. Moreover,
MoSiP is found to be a fully gapped superconductor with
strong electron-phonon coupling. First-principles calculations suggest that the
enhancement of electron-phonon coupling is possibly due to the shift of the
Fermi level, which is induced by electron doping. The calculations also reveal
the nontrivial band topology in MoSi. The and upper critical
field in MoSiP are fairly high among pseudobinary compounds.
Both of them are higher than those in NbTi, making future applications
promising. Our results suggest that the WSi-type compounds are ideal
platforms to search for new superconductors. By examinations of their band
topologies, more candidates for topological superconductors can be expected in
this structural family.Comment: 15 pages, 5 figures. Supplementary Information availabe at the
corresponding DO
Searching for Black Hole Candidates by LAMOST and ASAS-SN
Most dynamically confirmed stellar-mass black holes (BHs) and their candidates were originally selected from X-ray outbursts. In the present work, we search for BH candidates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey using the spectra along with photometry from the All Sky Automated Survey for SuperNovae (ASAS-SN), where the orbital period of the binary may be revealed by the periodic light curve, such as the ellipsoidal modulation type. Our sample consists of nine binaries, where each source contains a giant star with large radial velocity variation (ΔV_R ≳ 70 km s^(-1)) and periods known from light curves. We focus on the nine sources with long periods (T_(ph) > 5 days) and evaluate the mass M_2 of the optically invisible companion. Since the observed ΔV_R from only a few repeating spectroscopic observations is a lower limit of the real amplitude, the real mass M_2 can be significantly higher than the current evaluation. It is likely an efficient method to place constraints on M 2 by combining ΔV_R from LAMOST and T_(ph) from ASAS-SN, particularly by the ongoing LAMOST Medium Resolution Survey
Extremely long quasiparticle spin lifetimes in superconducting aluminium using MgO tunnel spin injectors
There has been an intense search in recent years for long-lived
spin-polarized carriers for spintronic and quantum-computing devices. Here we
report that spin polarized quasi-particles in superconducting aluminum layers
have surprisingly long spin-lifetimes, nearly a million times longer than in
their normal state. The lifetime is determined from the suppression of the
aluminum's superconductivity resulting from the accumulation of spin polarized
carriers in the aluminum layer using tunnel spin injectors. A Hanle effect,
observed in the presence of small in-plane orthogonal fields, is shown to be
quantitatively consistent with the presence of long-lived spin polarized
quasi-particles. Our experiments show that the superconducting state can be
significantly modified by small electric currents, much smaller than the
critical current, which is potentially useful for devices involving
superconducting qubits
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