New superconducting superhydride LaC2H8 at relatively low stabilization pressure

High-Tcsuperconductivity in doped molecular superconductors ofK4B8-xMxH32(M = C, N) under high pressure

Stabilized and metallic light elements hydrides have provided a potential route to achieve the goal of room-temperature superconductors at moderate or ambient pressures. Here, we have performed systematic DFT theoretical calculations to examine the effects of different light elements C and N atoms doped in cubic K4B8H32hydrides on the superconductivity at low pressures. As a result of various atoms substituting, we have found that metallic K4B_{8-x}MxH32(M = C, N) hydrides are dynamically stable at 50 GPa, band structures and density of states (DOS) indicate that sizeableTccorrelates with a high B-H DOS at the Fermi level. With the increasing of B atoms in K4B_{8-x}MxH32hydrides, the DOS values at Fermi level have been improved due to the delocalized electrons in B-H bonds, which result in strong electron-phonon coupling (EPC) interaction and increase theTcfrom 19.04 to 77.07 K for KC2H8and KB2H8at 50 GPa. The NH4unit in stable K4B7NH32hydrides has weakened the EPC and led to lowTcvalue of 21.47 K. Our results suggest the light elements hydrides KB2H8and K4B7CH32could estimate highTcvalues at 50 GPa, and the boron hydrides would be potential candidates to design or modulate hydrides superconductors with highTcat moderate or ambient pressures.

Strategies for improving the superconductivity of hydrides under high pressure

The successful prediction and confirmation of unprecedentedly high-temperature superconductivity in compressed hydrogen-rich hydrides signify a remarkable advancement in the continuous quest for attaining room-temperature superconductivity. The recent studies have established a broad scope for developing binary and ternary hydrides and illustrated correlation between specific hydrogen motifs and high-Tcs under high pressures. The analysis of the microscopic mechanism of superconductivity in hydrides suggests that the high electronic density of states at the Fermi level (EF), the large phonon energy scale of the vibration modes and the resulting enhanced electron-phonon coupling are crucial contributors towards the high-Tcphonon-mediated superconductors. The aim of our efforts is to tackle forthcoming challenges associated with elevating theTcand reducing the stabilization pressures of hydrogen-based superconductors, and offer insights for the future discoveries of room-temperature superconductors. Our present Review offers an overview and analysis of the latest advancements in predicting and experimentally synthesizing various crystal structures, while also exploring strategies to enhance the superconductivity and reducing their stabilization pressures of hydrogen-rich hydrides.