论文标题
扩展系统的基于平面波的随机确定性密度理论
Plane-Wave-Based Stochastic-Deterministic Density Functional Theory for Extended Systems
论文作者
论文摘要
传统的有限温度Kohn-Sham密度功能理论（KSDFT）在电子数或高温下具有不利的缩放。 KSDFT中基地密度的评估可以用Chebyshev Trace（CT）方法代替。另外，在CT方法中使用随机轨道会导致随机密度的功能理论[Phys。莱特牧师。 111，106402（2013）]（SDFT）及其改进的理论，混合随机性确定性密度功能理论[Phys。莱特牧师。 125，055002（2020）]（MDFT）。我们已经在第一原理程序包算盘中实现了以上四种方法。所有四种方法均基于平面波基础设置，该基础使用规范的伪电势和周期性的边界条件，并在布里群区域使用$ k $ - 点采样。通过使用KSDFT计算结果作为基准，我们通过检查一系列物理特性，系统地评估了CT，SDFT和MDFT方法的准确性和效率，其中包括电子密度，自由能，原子力，压力和少数凝结相系统的状态密度和密度。结果表明，我们对CT，SDFT和MDFT的实现不仅以很高的精度重现KSDFT结果，而且在KSDFT方法中也具有多种优势。我们希望这些方法在研究高温和大尺寸的扩展系统（例如温暖的密度物质和密集的血浆）方面有很大帮助。
Traditional finite-temperature Kohn-Sham density functional theory (KSDFT) has an unfavorable scaling with respect to the electron number or at high temperatures. The evaluation of the ground-state density in KSDFT can be replaced by the Chebyshev trace (CT) method. In addition, the use of stochastic orbitals within the CT method leads to the stochastic density functional theory [Phys. Rev. Lett. 111, 106402 (2013)] (SDFT) and its improved theory, mixed stochastic-deterministic density functional theory [Phys. Rev. Lett. 125, 055002 (2020)] (MDFT). We have implemented the above four methods within the first-principles package ABACUS. All of the four methods are based on the plane-wave basis set with the use of norm-conserving pseudopotentials and the periodic boundary conditions with the use of $k$-point sampling in the Brillouin zone. By using the KSDFT calculation results as benchmarks, we systematically evaluate the accuracy and efficiency of the CT, SDFT, and MDFT methods via examining a series of physical properties, which include the electron density, the free energy, the atomic forces, stress, and density of states for a few condensed phase systems. The results suggest that our implementations of CT, SDFT, and MDFT not only reproduce the KSDFT results with a high accuracy, but also exhibit several advantages over the tradition KSDFT method. We expect these methods can be of great help in studying high-temperature and large-size extended systems such as warm dense matter and dense plasma.
