PNNL

Abstract

The spin of diffuse electrons has been proposed in the literature as qubits in the literature as qubit for quantum hardware applications. Here we provide the first investigation of the thermal stability for a newly reported family of materials with diffuse electrons. This material has a diamond-like grid of Li+ centers bridged by diamine chains NH2(CH2)nH2N of varying carbon length. The tetracoordinated Li(NH2R) center is surrounded by one diffuse electron solvated by the N-H bonds. Previous work has demonstrated the tunability of the electronic structure of this material, with short chain lengths producing a metallic material and longer a semiconductor. Density functional theory-based ab initio molecular dynamics simulations are employed to characterize the thermal stability and melting point of the crystalline material. Calculations show that the thermal stability ranges from 100-220 K, primarily depending on the carbon chain length, with longer chains increasing the stability. Melting of the material is characterized by dissociation of the diamine coordination and formation of disordered clumps of undercoordinated Li-diamine centers. These melting points are well above temperatures used in typical quantum computing applications. The computational study provides insight into avenues for the future development of similar materials and the improvement of their stability.