Abstract：
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 K4B8-xMxH32(M = C, N) hydrides are dynamically stable at 50 GPa, band structures and density of states indicate that sizeableTccorrelates with a high B-H density of states at the Fermi level. With the increasing of B atoms in K4B8-xMxH32hydrides, the density of states 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 low Tc value 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.
摘要：
稳定和金属轻元素氢化物提供了在中等或环境压力下实现室温超导体目标的潜在途径。这里,我们进行了系统的DFT理论计算，以检查在低压下立方K4B8H32氢化物中掺杂不同轻元素C和N原子对超导性的影响。由于各种原子的取代，我们发现金属K4B8-xMxH32(M=C，N)氢化物在50GPa时动态稳定，能带结构和态密度表明sizeableTc与费米能级的高B-H态密度相关。随着K4B8-xMxH32氢化物中B原子的增加，由于B-H键中的离域电子，费米能级的态密度值得到了提高，导致强的电子-声子耦合（EPC）相互作用，并在50GPa时将KC2H8和KB2H8的Tc从19.04增加到77.07K。稳定的K4B7NH32氢化物中的NH4单元削弱了EPC并导致21.47K的低Tc值。我们的结果表明，轻元素氢化物KB2H8和K4B7CH32可以估计50GPa的高Tc值，氢化硼将是设计或调制具有高Tcat中等或环境压力的氢化物超导体的潜在候选者。
