Nodeless Superconductivity in Kagome Metal CsV3Sb5 with and without Time Reversal Symmetry Breaking.

The kagome metal CsV3Sb5 features an unusual competition between the charge-density-wave (CDW) order and superconductivity. Evidence for time reversal symmetry breaking (TRSB) inside the CDW phase has been accumulating. Hence, the superconductivity in CsV3Sb5 emerges from a TRSB normal state, potentially resulting in an exotic superconducting state. To reveal the pairing symmetry, we first investigate the effect of nonmagnetic impurity. Our results show that the superconducting critical temperature is insensitive to disorder, pointing to conventional s-wave superconductivity. Moreover, our measurements of the self-field critical current (Ic,sf), which is related to the London penetration depth, also confirm conventional s-wave superconductivity with strong coupling. Finally, we measure Ic,sf where the CDW order is removed by pressure and superconductivity emerges from the pristine normal state. Our results show that s-wave gap symmetry is retained, providing strong evidence for the presence of conventional s-wave superconductivity in CsV3Sb5 irrespective of the presence of the TRSB.

Patterned diamond anvils prepared via laser writing for electrical transport measurements of thin quantum materials under pressure.

Quantum materials exhibit intriguing properties with important scientific values and huge technological potential. Electrical transport measurements under hydrostatic pressure have been influential in unraveling the underlying physics of many quantum materials in bulk form. However, such measurements have not been applied widely to samples in the form of thin flakes, in which new phenomena can emerge, due to the difficulty in attaching fine wires to a thin sample suitable for high-pressure devices. Here, we utilize a home-built direct laser writing system to functionalize a diamond anvil to directly integrate the capability of conducting electrical transport measurements of thin flakes with a pressure cell. With our methodology, the culet of a diamond anvil is equipped with a set of custom-designed conducting tracks. We demonstrate the superiority of these tracks as electrodes for the studies of thin flakes by presenting the measurement of pressure-enhanced superconductivity and quantum oscillations in a flake of MoTe2.

Synthesis, characterisation and photophysical study of alkynylrhenium(I) tricarbonyl diimine complexes and their metal-ion coordination-assisted metallogelation properties.

A series of alkynylrhenium(I) tricarbonyl diimine complexes has been synthesized and characterized. A blue shift of the intense low-energy MLCT absorption band in the visible region was observed upon coordination of Cu(I) or Ag(I). This class of complexes has been found to show rich thermotropic gelation behaviour upon Cu(I) or Ag(I) coordination with their morphology characterized by SEM. Their variable-temperature UV/Vis absorption and emission properties have also been studied. A blue shift in the MLCT absorption band and the switching on of luminescence were observed upon sol-gel transition.

Synthesis and characterization of luminescent rhenium(I) tricarbonyl diimine complexes with a triarylboron moiety and the study of their fluoride ion-binding properties.

A series of alkynylrhenium(I) tricarbonyl diimine complexes with a triarylboron moiety has been synthesized and characterized. The binding properties of the complex toward fluoride ions have been studied using electronic absorption and emission spectroscopy and were further supported by (19)F NMR binding experiments.