论文标题
预测范德华材料中的异常量子约束效应
Predicting Anomalous Quantum Confinement Effect in van der Waals Materials
论文作者
论文摘要
已知具有范德华键键的材料表现出量子限制效应，其中三维（3D）材料实现的电子带隙低于其二维（2D）对应物的电子带隙。但是，存在异常量子限制效应（AQCE）的可能性，其中带隙趋势被逆转。在这项工作中，我们在计算上确定了这种AQCE发生的材料。使用密度函数理论（DFT），我们计算了〜1000 OptB88VDW（半本地功能），〜50 HSE06和〜50 PBE0（杂交功能）的散装型带及其相应的单层在Jarvis-DFT数据库中。 OPTB88VDW标识了65个AQCE材料，但是混合功能仅在14例中证实此类发现。 Some of the AQCE systems identified through HSE06 and PBE0 are: hydroxides or oxide hydroxide compounds (AlOH2, Mg(OH)2, Mg2H2O3, Ni(OH)2, SrH2O3) as well as Sb-halogen-chalcogenide compounds (SbSBr, SbSeI) and alkali-chalcogenides (RbLiS and RbLiSe).基于带构建和预测的状态密度的详细电子结构分析通常表明，AQCE通常以单层中的传导带的降低以及PZ电子轨道贡献的相应变化，而Z是2D情况下的非晶状体方向。我们认为，我们的计算结果将促进实验验证结果的努力，并会对基于低维材料的带隙工程应用产生影响。
Materials with van der Waals-bonding are known to exhibit quantum confinement effect, in which the electronic bandgap of the three-dimensional (3D) realization of a material is lower than that of its two-dimensional (2D) counterpart. However, the possibility of an anomalous quantum confinement effect (AQCE) exists, where the bandgap trend is reversed. In this work, we computationally identify materials for which such AQCE occurs. Using density functional theory (DFT), we compute ~1000 OptB88vdW (semi-local functional), ~50 HSE06 and ~50 PBE0 (hybrid functional) bandgaps for bulk and their corresponding monolayers in the JARVIS-DFT database. OptB88vdW identifies 65 AQCE materials, but the hybrid functionals only confirm such finding in 14 cases. Some of the AQCE systems identified through HSE06 and PBE0 are: hydroxides or oxide hydroxide compounds (AlOH2, Mg(OH)2, Mg2H2O3, Ni(OH)2, SrH2O3) as well as Sb-halogen-chalcogenide compounds (SbSBr, SbSeI) and alkali-chalcogenides (RbLiS and RbLiSe). A detailed electronic structure analysis, based on band-structure and projected density of states, shows AQCE is often characterized by lowering of the conduction band in the monolayer and corresponding changes in the pz electronic orbital contribution, with z being the non-periodic direction in the 2D case. We believe our computational results would spur the effort to validate the results experimentally and will have impact on bandgap engineering applications based on low-dimensional materials.
