arXiv subjects

Zhongjin Wu

Publications and source records attributed to Zhongjin Wu.

6 recordsLinked to original sources

arXiv2026

Soft point-contact Andreev reflection spectroscopy in a palm-type cubic anvil-pressure cell

We have implemented soft point-contact Andreev reflection spectroscopy (PCARS) in a palm-type cubic anvil pressure cell by combining a substrate anchoring strategy with an external wire-splitting technique. This design enables the stable formation of multiple point contact junctions under hydrostatic pressures up to 15 GPa. Benchmark measurements on the elemental superconductor Nb demonstrate high reproducibility and yield a zero-temperature superconducting gap with a gap ratio of 3.3. We further apply this technique to the Kagome metal superconductor CsCr3Sb5 and the bilayer nickelate superconductor La2PrNi2O7. Pronounced zero-bias conductance peaks are observed, and their evolution with temperature, magnetic field and applied pressure is investigated, together with the superconducting gap magnitude and possible pairing symmetries. These measurements provide spectroscopic evidence consistent with unconventional superconductivity in these materials. Our work establishes a robust experimental platform that bridges macroscopic electrical transport and microscopic spectroscopic probes, opening a new avenue for investigating pairing symmetry in a wide range of pressure-induced unconventional superconductors.

cond-mat.supr-con↗

arXiv2026

Anomalous Structural Response of Quasi-One-Dimensional Antiferromagnetic Metal KMn6Bi5 under high pressure

We report high-pressure single-crystal X-ray diffraction measurements on the quasi-one-dimensional (Q1D) antiferromagnetic metal KMn6Bi5 up to 12.5 GPa, revealing the detailed pressure evolution of its atomic coordination environment. We find that the lattice exhibits pronounced anisotropic compressibility-the relative changes in the a and b lattice parameters reach a/a0=0.91 and b/b0 = 0.94 at 12.5 GPa-and a distinct structural anomaly emerges near 11 GPa without any symmetry-breaking. Detailed structural analysis further uncovers an anomalous hardening of the Mn nanotubes between 5 and 11 GPa, followed by a configuration optimization of the Mn/Bi nanotubes around 11 GPa. These features correlate closely with the reported pressure-temperature phase diagram of KMn6Bi5 and compare favorably with the chemical pressure effects induced by substituting K with Na, Rb, or Cs. Our findings provide key microscopic insights into how coordination environment modulation governs the stability of electronic orders in low-dimensional systems.

cond-mat.mtrl-sci↗

arXiv2026

Structural responses incipient to pressure-driven antiferromagnetic quantum critical point of van der Waals heavy-fermion metal CeSiI

CeSiI is a van der Waals heavy-fermion metal recently found to exhibit unconventional superconductivity near a pressure-induced antiferromagnetic quantum critical point (QCP) at Pc =6 GPa. Here, we report a comprehensive single-crystal X-ray diffraction study of CeSiI under high pressures up to 8.3 GPa at room temperature, revealing subtle structural responses that precede pressure-driven QCP. We find that the unit-cell volume decreases smoothly upon compression without showing any structural phase transition in the investigated pressure range. Intriguingly, we observe abrupt and concurrent anisotropic responses of the lattice parameters around Pc =6 GPa, i.e., the a-axis contracts while the c-axis enlongated suddenly, with the unit-cell volume smoothily varies with pressure. Structural refinements further show that these lattice anomalies primarily originate from changes of Ce-Ce and Ce-Si bond lengths, as well as a flattening of the inner honeycomb Si layer within the CeSiI monolayer around Pc. Our findings establish an interesting case linking pressure-driven electronic transition of QCP at low temperatures to incipient structural responses at room temperature, thereby providing fresh insight into the pressure-temperature phase diagram of CeSiI.

cond-mat.str-el↗

arXiv2023

The Effect of Ionic Spin on Multiferroic of Orthorhombic Perovskite

To investigate the influence of ion spin on the coupling between ferromagnetism and ferroelectricity in type II multiferroic perovskite, we prepared the multiferroic perovskite Er0.9La0.1Cr0.8Fe0.2O3 (ELCFO) using the sol-gel method, and explored the macroscopic magnetic properties of ELCFO through Mössbauer spectrum and magnetic testing. The thermal magnetic curve was analyzed to examine the state and change of each ionic spin in the ELCFO system at different temperature ranges, and the role of ionic spin in the coupling between ferromagnetism and ferroelectricity was investigated. This study provides a theoretical basis for further research on multiferroic perovskites and has practical implications.

cond-mat.mtrl-sci↗

arXiv2023

Calculation of Special Spin Behavior of Dy3+ in DyFe1-xCrxO3 System by Molecular Field Model

In this study, the sol-gel method synthesized the magnetic measurement and analysis of single-phase polycrystalline perovskite DyFe1-xCrxO3 (DFCO). The experimental data were fitted and calculated by a four-sublattice molecular field model. Unlike previous studies, we found that in DyFe1-xCrxO3, the spin of the A-site rare earth ion Dy3+ also changed simultaneously with the spin reorientation of the Fe3+/Cr3+ ions. The effective spin is defined as the projection of the A site's total spin on the B site's spin plane, and the curve of temperature changes is obtained after fitting. With this theory, a very accurate thermomagnetic curve is obtained by fitting. This is convincing and, at the same time, provides a reference for the development of spintronic devices in the future.

cond-mat.mtrl-sci↗

arXiv2022

Special spin behavior of rare earth ions at the A site of polycrystalline ErFe1-xCrxO3 (x = 0.1, 0.9)

Thermally induced spin control is one of the main directions for future spin devices. In this study, we synthesized single-phase polycrystalline ErFe1-xCrxO3 and combined the magnetization curves and Mössbauer spectra to determine the macroscopic magnetism at room temperature. The magnetization of the system at various temperatures is well simulated by molecular field theory. And it is found that under the DM interaction, not only the B-site ions undergo a reorientation process, but the spins of the A-site ions also change at the same time. The effective spin is defined as the projection of Er3+ on the Fe3+/Cr3+ spin plane, and the whole reorientation process is obtained by fitting. This study will complement the actual process of ErFe1-xCrxO3 spin reorientation and will lay a theoretical foundation for the fabrication of future spin-controlled devices.

cond-mat.mtrl-sci↗