We successfully grew the high-quality single crystal of Rb${}_{0.88}$Fe${}_{1.81}$Se${}_{2}$, which shows a clear superconducting transition in magnetic susceptibility and electrical resistivity. Resistivity onset ${T}_{\mathrm{c}}$ at 32.1 K zero resistivity 30 K. From low-temperature iso-magnetic-field magnetoresistance, large upper critical field ${H}_{\mathrm{c}2}$(0) has been estimated to be as high 180 T for applied within $\mathit{ab}$ plane 59 along $c$ axis. The anisotropy...

In a semimetal, both electrons and holes contribute to the density of states at Fermi level. The small band overlaps multiband effects engender novel electronic properties. We show that moderate hydrostatic pressure effectively suppresses gap in elemental semiconductor black phosphorus. An topological transition takes place approximately 1.2 GPa, above which phosphorus evolves into semimetal state is characterized by colossal positive magnetoresistance nonlinear field dependence Hall...

We measure the resistivity and magnetic susceptibility in temperature range from 5 K to 600 for single crystals $A$Fe$_{2-y}$Se$_2$ ($A$ = K$_{0.8}$, Rb$_{0.8}$, Cs$_{0.8}$, Tl$_{0.5}$K$_{0.3}$ Tl$_{0.4}$Rb$_{0.4}$). A sharp superconducting transition is observed low susceptibility, shows 100% Meissner volume fraction all crystals, while an antiferromagnetic at Neel ($T_N$) as high 500 540 depending on A. It indicates coexistence of superconductivity antiferromagnetism. increase arises...

We report on experimental demonstration of a new type nanoelectromechanical resonators based black phosphorus crystals. Facilitated by highly efficient dry transfer technique, crystalline flakes are harnessed to enable drumhead vibrating at high and very frequencies (HF VHF bands, up ~100MHz). investigate the resonant vibrational responses from crystals devising both electrical optical excitation schemes, in addition measuring undriven thermomechanical motions these suspended nanostructures....

We systematically investigated the in-plane resistivity anisotropy of electron-underdoped EuFe(2-x)Co(x)As(2) and BaFe(2-x)Co(x)As(2) hole-underdoped Ba(1-x)K(x)Fe(2)As(2). Large was found in former samples, while tiny detected latter ones. When it is detected, starts above structural transition temperature increases smoothly through it. As lowered further, takes a dramatic enhancement magnetic temperature. that universally tied to presence T-linear behavior resistivity. Our results...

We successfully grew the high-quality single crystals of ${A}_{x}$Fe${}_{2}$Se${}_{2}$ ($A$ $=$ K and Cs) by self-flux method. Sharp superconducting transition was observed for both types crystals. The show onset temperatures (${T}_{\mathrm{c}}$) 31 30 Cs compounds, respectively, with nearly 100$%$ superconductive shielding fraction. quite high resistivity in normal state more than 160 1300 $\mathrm{m}\ensuremath{\Omega}$ cm maximum ${\mathrm{K}}_{x}$Fe${}_{2}$Se${}_{2}$...

We measured the resistivity and magnetic susceptibility to map out phase diagram of single crystalline NaFe$_{1-x}$Co$_x$As. Replacement Fe by Co suppresses both structural transition, while enhances superconducting transition temperature ($T_{\rm c}$) component fraction. Magnetic exhibits temperature-linear dependence in high temperatures up 500 K for all samples, but such behavior suddenly breaks down non-superconducting overdoped crystal, suggesting that superconductivity is closely...

We measure the magnetotransport properties of three-dimensional Dirac semimetal Cd_{3}As_{2} single crystal under magnetic fields up to 36 T. Shubnikov-de Haas (SdH) oscillations are clearly resolved and n=1 Landau level is reached. A detailed analysis on intercept index plot reveals a significant dependence SdH phase factor orientation applied field. When field in [001] direction, i.e., along fourfold screw axis tetragonal structure, nontrivial π Berry phase, as predicted for fermions,...

A series of high quality NaFe$_{1-x}$Cu$_x$As single crystals has been grown by a self-flux technique, which were systematically characterized via structural, transport, thermodynamic, and pressure measurements. Both the structural magnetic transitions are suppressed Cu doping, bulk superconductivity is induced doping. Superconducting transition temperature ($T_c$) initially enhanced from 9.6 to 11.5 K then with further phase diagram similar NaFe$_{1-x}$Co$_x$As obtained except that...

We measured the resistivity and specific heat of CsFe${}_{2}$As${}_{2}$ single crystals, which were grown by using a self-flux method. The crystal shows sharp superconducting transition at 1.8 K with width 0.1 K. pronounced jump in indicate high quality crystals. A large $\ensuremath{\Delta}{C}_{p}/{T}_{c}$ accompanying very low ${T}_{c}$, nonexponential dependence lowest temperature $\ensuremath{\Delta}{C}_{p}/T$ an ${H}^{1/2}$ $\ensuremath{\Delta}\ensuremath{\gamma}(H)$ are observed...

We report the magnetism and transport measurements of CaCo$_2$As$_2$ Ca$_{0.9}$Sr$_{0.1}$Co$_2$As$_2$ single crystals. Antiferromagnetic transition was observed at about 70 K 90 for Ca$_{0.9}$Sr$_{0.1}$Co$_2$As$_2$, respectively. Magnetism magnetoresistance reveal metamagnetic from an antiferromagnetic state to a ferromagnetic with critical field 3.5 T 1.5 respectively along c-axis these two materials low temperature. For ab-plane, spins can also be fully polarized above 4.5...

Sizable single-crystalline samples of Ca$_{10}$(Pt$_3$As$_8$)((Fe$_{1-x}$Pt$_x$)$_2$As$_2$)$_5$ (the 10-3-8 phase) with 0$\leq x<$0.1 have been grown and systematically characterized via X-Ray diffraction, magnetic, transport measurements. The undoped sample is a heavily doped semiconductor no sign magnetic order down to 2 K. With increasing Pt content, the metallic behavior appears superconductivity realized for $x\geq$0.023. $T_{\rm c}$ rises its maximum approximately 13.6 K at doping...

High-quality K(Fe${}_{1\ensuremath{-}x}$Co${}_{x}$)${}_{2}$As${}_{2}$ single crystals have been grown by using the KAs flux method. Instead of increasing superconducting transition temperature ${T}_{\mathrm{c}}$ through electron doping, we find that Co impurities rapidly suppress down to zero at only $x\ensuremath{\approx}$ 0.04. Such an effective suppression is quite different from observed in Ba${}_{0.5}$K${}_{0.5}$Fe${}_{2}$As${}_{2}$ with multiple nodeless gaps. Thermal conductivity...

We have performed high hydrostatic pressure resistivity measurements (up to 1.7 GPa) on the newly discovered superconductor AxFe2Se2 (A = K and Cs) single crystals. Two batches of crystals KxFe2Se2 with different transition temperatures (Tc) were used study effect pressure. The Tc first one gradually decreases increasing from 32.6 at ambient While a dome-like behavior was observed for crystal 31.1 K, reaches its maximum value 32.7 0.48 GPa. This indicates that there exists an optimal doping...

We report the structural, magnetic, and electronic transport properties of SrFe${}_{2\ensuremath{-}x}$Cu${}_{x}$As${}_{2}$ single crystals grown by a self-flux technique. Both SrCu${}_{2}$As${}_{2}$ SrFe${}_{2}$As${}_{2}$ crystallize in ThCr${}_{2}$Si${}_{2}$-type (122-type) structure at room temperature, but exhibit distinct magnetic properties. According to x-ray photoelectron spectroscopy Cu $2p$ core line position, resistivity, susceptibility, positive Hall coefficient, is an...

The new layered manganese oxychalcogenides (LaO)$_2$Mn$_2$Se$_2$O and (BaF)$_2$Mn$_2$Se$_2$O, isostructural to (LaO)$_2$Fe$_2$Se$_2$O, were synthesized by using solid state reaction. single crystals of former compound also successfully grown high temperature fusion method. polycrytalline samples showed the insulating behavior, with activation energy gaps about 278 meV 416 for respectively. magnetic susceptibility indicated an antiferromagnetic (AFM) transition at around 160K strong...

We measured the transport properties and susceptibility of single crystals Ca$_{1-x}$La$_x$Fe$_2$As$_2$(x=0, 0.05, 0.1, 0.15, 0.19 0.25). Large in-plane resistivity anisotropy similar to that in Co-doped 122 iron-pnictides is observed although no transition metals were introduced FeAs-plane. The gradually increases with La doping below T$_{SDW}$, being different from hole-doped superconductors. susceptibilities samples show leads suppression SDW induces a Curie-Weiss-like behavior at low...

The mixed-metal-network layered compound TaFe${}_{1+x}$Te${}_{3}$ has the TaFeTe${}_{3}$ layers formed by Ta-Fe bonded network (Fe1) sandwiched with tellurium and excess iron atoms (Fe2) partially occupying interstitial site of tetrahedral (Ta,Fe)Te at random, which are similar to in iron-based high-${T}_{c}$ superconductor Fe${}_{1+y}$Te. antiferromagnetic (AFM) transition Fe1 zigzag chains spin flop these Fe2 under a high magnetic field studied through susceptibility, magnetoresistance...

We establish the phase diagram of Eu${}_{1\ensuremath{-}x}$La${}_{x}$Fe${}_{2}$As${}_{2}$ system as a function doping level $x$ and pressure by measuring resistivity magnetic susceptibility. Increased can suppress spin-density-wave (SDW) structural transitions very efficiently, while enhancing antiferromagnetic (AFM) transition temperature $T$${}_{N}$ Eu${}^{2+}$. Superconductivity coexists with SDW order at low always Eu${}^{2+}$ AFM order. The results suggest that spin dynamics is...

Circular RNA (circRNA) has been found to mediate ulcerative colitis (UC) progression by regulating intestinal mucosal barrier function. However, the role of circSOD2 in UC process and its underlying molecular mechanism still need be further elucidated.