In a latest experimental advance, graphene-like and insulating BeO monolayer was successfully grown over silver surface by molecular beam epitaxy (ACS Nano 15(2021), 2497). Inspired by this accomplishment, in this work we conduct first-principles based simulations to explore the electronic, mechanical properties and thermal conductivity of graphene-like BeO, MgO and CaO monolayers. The considered nanosheets are found to show desirable thermal and dynamical stability. BeO monolayer is found to show remarkably high elastic modulus and tensile strength of 408 and 53.3 GPa, respectively. The electronic band gap of BeO, MgO and CaO monolayers are predicted to be 6.72, 4.79, and 3.80 eV, respectively, using the HSE06 functional. On the basis of iterative solution of the Boltzmann transport equation, the room temperature lattice thermal conductivity of BeO, MgO and CaO monolayers are predicted to be 385, 64 and 15 W/mK, respectively. Our results reveal substantial decline in the electronic band gap, mechanical strength and thermal conductivity by increasing the weight of metal atoms. This work highlights outstandingly high thermal conductivity, carrier mobility and mechanical strength of insulating BeO nanosheets and suggest them as promising candidates to design strong and insulating components with high thermal conductivities.

在最新的实验进展中，通过分子束外延在银表面成功生长了类石墨烯和绝缘 BeO 单层 ( ACS Nano 15(2021), 2497）。受这一成就的启发，在这项工作中，我们进行了基于第一性原理的模拟，以探索类石墨烯 BeO、MgO 和 CaO 单层的电子、机械性能和热导率。发现所考虑的纳米片显示出理想的热稳定性和动态稳定性。发现 BeO 单层显示出非常高的弹性模量和拉伸强度，分别为 408 和 53.3 GPa。使用 HSE06 函数预测 BeO、MgO 和 CaO 单层的电子带隙分别为 6.72、4.79 和 3.80 eV。根据玻尔兹曼输运方程的迭代求解，预测 BeO、MgO 和 CaO 单层的室温晶格热导率分别为 385、64 和 15 W/mK。我们的结果显示电子带隙大幅下降，通过增加金属原子的重量来提高机械强度和导热性。这项工作突出了绝缘 BeO 纳米片的出色导热性、载流子迁移率和机械强度，并建议它们作为设计具有高导热性的坚固绝缘组件的有希望的候选者。