Boson Subsidiary Solver (BoSS) v1.1

How best to model systems of interacting electrons in an accurate and computationally efficient manner is an outstanding problem in theoretical and computational materials science. For materials where strong electronic interactions are primarily of a localized character and act within a subspace of localized quantum states on separate atomic sites (e.g., in transition metal and rare-earth compounds), their electronic behaviors are typically described by the Hubbard model and its extensions. In this work, we describe BoSS (Boson Subsidiary Solver), a software implementation of the subsidiary-boson (also known as slave-boson or auxiliary-boson) method appropriate for describing a variety of extended Hubbard models, namely p - d models that include both the interacting atomic sites (“d” states) and non-interacting or ligand sites (“p” states). We provide a theoretical background, a description of the equations solved by BoSS, an overview of the algorithms used, the key input/output and control variables of the software program, and tutorial examples of its use featuring band renormalization in SrVO3, Ni 3d multiplet structure in LaNiO3, and the relation between the formation of magnetic moments and insulating behavior in SmNiO3. BoSS interfaces directly with popular electronic structure codes: it can read the output of the Wannier90 software package [1], [2] which postprocesses results from workhorse electronic structure software such as Quantum Espresso [3] or VASP [4].如何以高精度且计算高效的方式对相互作用电子系统进行建模，是理论与计算材料科学领域的一项亟待解决的突出问题。对于强电子相互作用主要表现为局域特性、且相互作用发生在独立原子位点上的局域量子态所构成的子空间中的材料（例如过渡金属与稀土化合物），其电子行为通常可通过哈伯德模型（Hubbard model）及其拓展形式进行描述。本研究中，我们介绍了BoSS（玻色子附属求解器，Boson Subsidiary Solver）：一款基于附属玻色子方法（又称奴隶玻色子方法或辅助玻色子方法）的软件实现，适用于描述各类拓展哈伯德模型，即同时包含相互作用原子位点（“d”态）与非相互作用或配体位点（“p”态）的p-d模型。本工作中，我们将提供该软件的理论背景、BoSS所求解的方程说明、所用算法的整体概述、软件程序的核心输入/输出与控制变量，以及其使用的教程示例：涵盖SrVO₃中的能带重整化、LaNiO₃中的Ni 3d多重态结构，以及SmNiO₃中磁矩形成与绝缘行为间的关联。BoSS可直接对接主流电子结构计算软件：它能够读取Wannier90软件包[1][2]的输出结果，而Wannier90可对Quantum Espresso[3]或VASP[4]等常用电子结构计算软件的计算结果进行后处理。