Growth and Characterization of Transition Metal Phosphochalcogenide Compounds, Alloys, and Superlattices

小行星9308854 拟议研究的目标是应用一种称为货车德瓦尔斯外延的分子束外延变体来合成基于过渡金属磷硫族化物（MPX 3）化合物的新型化合物和超晶格。 追求这一领域的主要动机是与高温铜酸盐超导体的性质相似。 因此，将寻求替代的高Tc材料。 目前已知的过渡金属MPX 3化合物都是相关的反铁磁绝缘体，并且具有类似于MX 2化合物的准二维层状结构。 气相外延所允许的合成灵活性将允许有效的单电子带宽和有效的现场相关能的系统变化，以诱导绝缘体-金属转变，从而产生具有新的和潜在有用的传输，光学和磁性的材料。 具体地，i）已知MPX 3化合物的数量将增加到包括4d和5d金属，ii）随机合金M ′ yM 1-yPX 3将生长以诱导n型或p型掺杂，以及iii）将产生将MPX 3化合物与具有不同介电性质的各种层状材料组合的超晶格。 这些新材料和结构将通过各种技术来表征。 ***

9308854 Kevan The goal of the proposed research is to apply a variant of molecular beam epitaxy called van der Waals epitaxy to synthesize novel compounds and superlattices based upon transition metal phosphochalcogenide (MPX3) compounds. The primary motivation to pursue this area is a qualitative similarity to the high temperature cuprate superconductors. Alternative high Tc materials will thus be sought. The currently known transition metal MPX3 compounds are all correlated antiferromagnetic insulaators and have a quasi-two-dimensional layered structure similar to MX2 compounds. The synthetic flexibility allowed by vapor phase epitaxy will allow systematic variation of effective one-electron band widths and effective on-site correlation energies to induce an insulator-metal transition, thereby producing materials with novel and potentially useful transport, optical, and magnetic properties. Specifically, i) the number of known MPX3 compounds will be increased to include 4d and 5d metals, ii) random alloys M'yM1-yPX3 will be grown to induce n- or p-type doping, and iii) superlattices combining MPX3 compounds with a variety of layered maaaaterials having divergent dielectric properties will be produced. These new materials and structures will be characterized by a variety of techniques. ***