Development of a new Bridgman-type high-pressure cell by using built-in gasket up to 9.4 GPa and evaluation of deformation.

We have developed a built-in gasket for the Bridgman-type opposed-anvil high-pressure cell, featuring a PTFE (Teflon) capsule of ϕ 2.0 (1.5) × 2.

Pressure-induced linear enhancement of the superconducting transition in NdSrNiOthin films.

We report the pressure () effect on the superconducting transition temperatureand the upper critical fieldof infinite-layer NdSrNiOthin films by measuring the electrical transport properties under various hydrostatic pressures to 4.6 GPa. At ambient pressure, it shows the clear superconducting transition with∼ 10 K.

Piston-cylinder cell made of Ni-Cr-Al alloy for magnetic susceptibility measurements under high pressures in pulsed high magnetic fields.

We developed a metallic pressure cell made of 56Ni-40Cr-4Al (Ni-Cr-Al) alloy for use with a non-destructive pulse magnet and a magnetic susceptibility measurement apparatus with a proximity detector oscillator (PDO) in pulsed magnetic fields of up to 51 T under pressures of up to 2.1 GPa. Both the sample and sensor coil of the PDO were placed in the cell so that the magnetic signal from Ni-Cr-Al would not overlay the intrinsic magnetic susceptibility of the sample.

Bulk evidence of anisotropic s-wave pairing with no sign change in the kagome superconductor CsVSb.

The recently discovered kagome superconductors AVSb (A = K, Rb, Cs) exhibit unusual charge-density-wave (CDW) orders with time-reversal and rotational symmetry breaking. One of the most crucial unresolved issues is identifying the symmetry of the superconductivity that develops inside the CDW phase. Theory predicts a variety of unconventional superconducting symmetries with sign-changing and chiral order parameters.

Destabilization of the Charge Density Wave and the Absence of Superconductivity in ScVSn under High Pressures up to 11 GPa.

VSn ( = Sc, Y, or rare earth) is a new family of kagome metals that have a similar vanadium structural motif as VSb ( = K, Rb, Cs) compounds. Unlike VSb, ScVSn is the only compound among the series of VSn that displays a charge density wave (CDW) order at ambient pressure, yet it shows no superconductivity (SC) at low temperatures. Here, we perform a high-pressure transport study on the ScVSn single crystal to track the evolutions of the CDW transition and to explore possible SC.

Pressure-induced monotonic enhancement of T to over 30 K in superconducting PrSrNiO thin films.

The successful synthesis of superconducting infinite-layer nickelate thin films with the highest T ≈ 15 K has ignited great enthusiasm for this material class as potential analogs of the high-T cuprates. Pursuing a higher T is always an imperative task in studying a new superconducting material system. Here we report high-quality PrSrNiO thin films with T ≈ 17 K synthesized by carefully tuning the amount of CaH in the topotactic chemical reduction and the effect of pressure on its superconducting properties by measuring electrical resistivity under various pressures in a cubic anvil cell apparatus.

Anharmonic phonon interactions and the Kondo effect in a FeSe/SbTe/FeSe heterostructure: a proximity effect between ferromagnetic chalcogenide and di-chalcogenide.

In this report, we have introduced magnetic ordering into the nontrivial system of conventional topological insulators (TIs) by creating magnetic interfaces. In this context, antimony di-chalcogenide SbTe sandwiched between two thin layers of FeSe was prepared using the pulsed laser deposition (PLD) technique. The prepared heterostructure demonstrated good crystallinity along with homogeneous morphology displaying pyramid-shaped characteristic triangular islands.

Pressure-Induced Superconductivity of the Quasi-One-Dimensional Organic Conductor (TMTTF)TaF.

We investigated the superconductivity of (TMTTF)TaF (TMTTF: tetramethyl-tetrathiafulvalene) by conducting resistivity measurements under high pressure up to 8 GPa. A cubic anvil cell (CAC) pressure generator, which can produce hydrostatic high-pressure, was used for this study. Since the generalized temperature-pressure (-) diagram of (TMTF) ( = Se, S, : monovalent anion) based on (TMTTF)PF ( = 70 K and spin-Peierls: SP, = 15 K) was proposed by Jérome, exploring superconductivity states using high-pressure measurement beyond 4 GPa has been required to confirm the universality of the electron-correlation variation under pressure in (TMTTF) (TMTTF)TaF, which has the largest octahedral-symmetry counter anion TaF in the (TMTTF) series, possesses the highest charge-ordering (CO) transition temperature ( = 175 K) in (TMTTF) and demonstrates an anti-ferromagnetic transition ( = 9 K) at ambient pressure.

Evidence for pressure induced unconventional quantum criticality in the coupled spin ladder antiferromagnet CHNCuBr.

Quantum phase transitions in quantum matter occur at zero temperature between distinct ground states by tuning a nonthermal control parameter. Often, they can be accurately described within the Landau theory of phase transitions, similarly to conventional thermal phase transitions. However, this picture can break down under certain circumstances.

Pressured-induced superconducting phase with large upper critical field and concomitant enhancement of antiferromagnetic transition in EuTe.

We report an unusual pressure-induced superconducting state that coexists with an antiferromagnetic ordering of Eu moments and shows a large upper critical field comparable to the Pauli paramagnetic limit in EuTe. In concomitant with the emergence of superconductivity with T ≈ 3-5 K above P ≈ 6 GPa, the antiferromagnetic transition temperature T(P) experiences a quicker rise with the slope increased dramatically from dT/dP = 0.85(14) K/GPa for P ≤ P to 3.

Pressure-Induced Superconductivity up to 9 K in the Quasi-One-Dimensional KMn_{6}Bi_{5}.

The Mn-based superconductor is rare owing to the strong magnetic pair-breaking effect. Here we report on the discovery of pressure-induced superconductivity in KMn_{6}Bi_{5}, which becomes the first ternary Mn-based superconductor. At ambient pressure, the quasi-one-dimensional KMn_{6}Bi_{5} is an antiferromagnetic metal with T_{N}≈75  K.

Nearly Room-Temperature Ferromagnetism in a Pressure-Induced Correlated Metallic State of the van der Waals Insulator CrGeTe_{3}.

A complex interplay of different energy scales involving Coulomb repulsion, spin-orbit coupling, and Hund's coupling energy in 2D van der Waals (vdW) material produces a novel emerging physical state. For instance, ferromagnetism in vdW charge transfer insulator CrGeTe_{3} provides a promising platform to simultaneously manipulate the magnetic and electrical properties for potential device implementation using few nanometers thick materials. Here, we show a continuous tuning of magnetic and electrical properties of a CrGeTe_{3} single crystal using pressure.

Pressure Dependence of Superconducting Properties, Pinning Mechanism, and Crystal Structure of the FeMnSeTe Superconductor.

We have investigated the pressure () effect on structural (up to 10 GPa), transport [(): up to 10 GPa], and magnetic [((): up to 1 GPa)] properties and analyzed the flux pinning mechanism of the FeMnSeTe superconductor. The maximum superconducting transition temperature ( ) of 22 K with the coefficient of d /d = +2.6 K/GPa up to 3 GPa (d /d = -3.

Pressure-induced reconstitution of Fermi surfaces and spin fluctuations in S-substituted FeSe.

FeSe is a unique high-[Formula: see text] iron-based superconductor in which nematicity, superconductivity, and magnetism are entangled with each other in the P-T phase diagram. We performed [Formula: see text]Se-nuclear magnetic resonance measurements under pressures of up to 3.9 GPa on 12% S-substituted FeSe, in which the complex overlap between the nematicity and magnetism are resolved.

Continuous control of classical-quantum crossover by external high pressure in the coupled chain compound CsCuCl.

In solid materials, the parameters relevant to quantum effects, such as the spin quantum number, are basically determined and fixed at the chemical synthesis, which makes it challenging to control the amount of quantum correlations. We propose and demonstrate a method for active control of the classical-quantum crossover in magnetic insulators by applying external pressure. As a concrete example, we perform high-field, high-pressure measurements on CsCuCl, which has the structure of weakly-coupled spin chains.

Double Superconducting Dome and Triple Enhancement of T_{c} in the Kagome Superconductor CsV_{3}Sb_{5} under High Pressure.

CsV_{3}Sb_{5} is a newly discovered Z_{2} topological kagome metal showing the coexistence of a charge-density-wave (CDW)-like order at T^{*}=94  K and superconductivity (SC) at T_{c}=2.5  K at ambient pressure. Here, we study the interplay between CDW and SC in CsV_{3}Sb_{5} via measurements of resistivity, dc and ac magnetic susceptibility under various pressures up to 6.

Defect induced ferromagnetic ordering and room temperature negative magnetoresistance in MoTeP.

The magneto-transport, magnetization and theoretical electronic-structure have been investigated on type-II Weyl semimetallic MoTeP. The ferromagnetic ordering is observed in the studied sample and it has been shown that the observed magnetic ordering is due to the defect states. It has also been demonstrated that the presence of ferromagnetic ordering in effect suppresses the magnetoresistance (MR) significantly.

Strongly correlated superconductivity in a copper-based metal-organic framework with a perfect kagome lattice.

Metal-organic frameworks (MOFs), which are self-assemblies of metal ions and organic ligands, provide a tunable platform to search a new state of matter. A two-dimensional (2D) perfect kagome lattice, whose geometrical frustration is a key to realizing quantum spin liquids, has been formed in the π - conjugated 2D MOF [Cu(CS)] (Cu-BHT). The recent discovery of its superconductivity with a critical temperature of 0.

Experimental evidence for the existence of a second partially-ordered phase of ice VI.

Ice exhibits extraordinary structural variety in its polymorphic structures. The existence of a new form of diversity in ice polymorphism has recently been debated in both experimental and theoretical studies, questioning whether hydrogen-disordered ice can transform into multiple hydrogen-ordered phases, contrary to the known one-to-one correspondence between disordered ice and its ordered phase. Here, we report a high-pressure phase, ice XIX, which is a second hydrogen-partially-ordered phase of ice VI.

High-pressure phase diagrams of FeSeTe: correlation between suppressed nematicity and enhanced superconductivity.

The interplay among magnetism, electronic nematicity, and superconductivity is the key issue in strongly correlated materials including iron-based, cuprate, and heavy-fermion superconductors. Magnetic fluctuations have been widely discussed as a pairing mechanism of unconventional superconductivity, but recent theory predicts that quantum fluctuations of nematic order may also promote high-temperature superconductivity. This has been studied in FeSeS superconductors exhibiting nonmagnetic nematic and pressure-induced antiferromagnetic orders, but its abrupt suppression of superconductivity at the nematic end point leaves the nematic-fluctuation driven superconductivity unconfirmed.

Fabrication and evaluation via nuclear quadrupole resonance of a palm cubic-anvil pressure cell.

A "palm" cubic-anvil pressure cell (PCAC) having an outer diameter of 60 mm, the smallest cubic-anvil cell to date, was fabricated to insert in a large-bore superconducting magnet. The pressure cell has a sample space of ϕ 2.5 × 1.

New phenomena of photo-luminescence and persistent luminescence of a Eu,Tb codoped CaBaPO phosphor under high hydrostatic pressure.

In this study, we present a photo-luminescence (PL) and persistent luminescence (PersL) investigation of Ca6BaP4O17:Eu2+,Tb3+ (CBPO:Eu,Tb) at high hydrostatic pressure in the range of 0-11.04 GPa. More importantly, there is a significant increase of PL intensity and extension of PersL duration time at a pressure point of ∼0.

Superconducting-Gap Anisotropy of Iron Pnictides Investigated via Combinatorial Microwave Measurements.

One of the most significant issues for superconductivity is clarifying the momentum-dependent superconducting gap Δ([Formula: see text]), which is closely related to the pairing mechanism. To elucidate the gap structure, it is essential to investigate Δ([Formula: see text]) in as many different physical quantities as possible and to crosscheck the results obtained in different methods with each other. In this paper, we report a combinatorial investigation of the superfluid density and the flux-flow resistivity of iron-pnictide superconductors; LiFeAs and BaFe(AsP) (x = 0.