Investigation of spin systems via ab initio quantum Monte Carlo and perturbation theory (B13*)

该项目的核心是，通过考虑密度泛函理论（DFT）的替代方法，对SFB/TR 49中研究的某些选定量子自旋系统的电子，自旋和声子性质进行准确描述。我们选择的方法包括从头计算量子蒙特卡罗技术和微扰展开技术。主要感兴趣的系统将是（1）具有不同程度的磁阻挫x的示例性三角晶格基铜卤化物Cs2 CuCl 4 <$xBrx和（2）各向异性金刚石链Cu 3（CO 3）2（OH）2（蓝铜矿）。

At the heart of this project is, by considering alternative methods to density functional theory (DFT), to provide an accurate description of the electronic, spin and phononic properties of some selected quantum spin systems studied within the SFB/TR 49. Our methods of choice include the ab initio quantum Monte Carlo technique and the perturbation expansion technique. Systems of primary interest will be (1) the exemplary triangular-lattice-based copper halides Cs2CuCl4¿xBrx with varying degrees of magnetic frustration x and (2) the anisotropic diamond chain Cu3(CO3)2(OH)2 (azurite).