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arXiv 2107.06128cond-mat.mtrl-sci
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一条通向合金高通量量子蒙特卡罗模拟的途径:二维(2D)$GaS_xSe_{1-x}$实例研究

A pathway towards high throughput Quantum Monte Carlo simulations for alloys: A case study of two-dimensional (2D) $GaS_xSe_{1-x}$

Daniel Wines, Kayahan Saritas, Can Ataca

摘要:

由于实验上不同结构的化学计量和局部原子有序性通常是未知的,因此使用计算方法研究合金一直是一项困难的任务。为了解决这个问题,第一性原理方法已经与统计方法相结合,例如集群扩展形式主义,以构建能量壳图,这有助于确定合金结构是否可以存在于自然界中。传统上,密度泛函理论(DFT)已经被用于这样的工作流程中。在这项工作中,我们建议使用化学精确的多体变分蒙特卡罗(VMC)和扩散蒙特卡罗(DMC)方法来构建合金系统的能量壳图,由于这样的方法对起始波函数和密度泛函的依赖性较弱,与DFT的电子数相似,并且已经证明了对各种材料的成功。为了以高吞吐量的方式进行这些模拟,我们提出了一种称为Jastrow共享的方法,该方法涉及在具有不同化学计量的合金之间回收优化的Jastrow参数。我们表明,这消除了额外的VMC Jastrow优化计算的需要,并导致显着的计算成本节省(平均节省1/4的总计算时间)。由于它是一种新的后过渡金属硫族化物合金系列,已在其几层的形式合成,我们使用单层$GaS_xSe_{1-x}$作为我们的工作流程的案例研究。通过广泛测试单层$GaS_xSe_{1-x}$的Jastrow共享程序并量化成本节约,我们演示了如何使用多体VMC和DMC方法实现合金的化学精确高通量模拟。

英文摘要:

The study of alloys using computational methods has been a difficult task due to the usually unknown stoichiometry and local atomic ordering of the different structures experimentally. In order to combat this, first-principles methods have been coupled with statistical methods such as the Cluster Expansion formalism in order to construct the energy hull diagram, which helps to determine if an alloyed structure can exist in nature. Traditionally, density functional theory (DFT) has been used in such workflows. In this work we propose to use chemically accurate many-body variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC) methods to construct the energy hull diagram of an alloy system, due to the fact that such methods have a weaker dependence on the starting wavefunction and density functional, scale similarly to DFT with the number of electrons, and have had demonstrated success for a variety of materials. To carry out these simulations in a high-throughput manner, we propose a method called Jastrow sharing, which involves recycling the optimized Jastrow parameters between alloys with different stoichiometries. We show that this eliminates the need for extra VMC Jastrow optimization calculations and results in a significant computational cost savings (on average 1/4 savings of total computational time). Since it is a novel post-transition metal chalcogenide alloy series that has been synthesized in its few-layer form, we used monolayer $GaS_xSe_{1-x}$ as a case study for our workflow. By extensively testing our Jastrow sharing procedure for monolayer $GaS_xSe_{1-x}$ and quantifying the cost savings, we demonstrate how a pathway towards chemically accurate high-throughput simulations of alloys can be achieved using many-body VMC and DMC methods.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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