Mineralizer-free synthesis of orthorhombic arsenic-phosphorus alloys

Phosphorus and arsenic belong to the same group of periodic table and especially the former is very intensively studied. Despite this, under normal conditions, phosphorus has an orthorhombic structure whereas arsenic is rhombohedral. Research concerning the orthorhombic allotrope of arsenic is very scarce due to its limited availability and in addition, As-P alloys have been predicted to possess unique features. In this manuscript, we studied the formation of As-P alloys using condensation of vapor in various As-P ratio in the range of 50 to 100 at. % of arsenic. We observed the formation of orthorhombic arsenic in the range of 50 to 70 at.% of arsenic, While for 80 at.% and 90 at.% the rhombohedral structure of arsenic remained unchanged. The formation of orthorhombic true van der Waals As-P alloys was obtained without addition of any mineralizers such as copper or tin iodides providing high purity material.