Electron density distribution in Si and Ge

using multipole, maximum entropy method

and pair distribution function analysis

R SARAVANAN^1,*, K S SYED ALI² and S ISRAEL³

¹Department of Physics, The Madura College, Madurai 625 011, India

²Department of Physics, Yadava College, Madurai 625 014, India

³Department of Physics, The American College, Madurai 625 002, India

^*Corresponding author. E-mail: saragow@dataone.in

Abstract. The local, average and electronic structure of the

semiconducting materials Si and Ge has been studied using multipole,

maximum entropy method (MEM) and pair distribution function (PDF)

analyses, using X-ray powder data. The covalent nature of bonding and

the interaction between the atoms are clearly revealed by the

two-dimensional MEM maps plotted on (1 0 0) and (1 1 0) planes and

one-dimensional density along [1 0 0], [1 1 0] and [1 1 1]

directions. The mid-bond electron densities between the atoms are

0.554 e/{\AA}$^{3}$ and 0.187 e/{\AA}$^{3}$ for Si and Ge

respectively. In this work, the local structural information has also

been obtained by analyzing the atomic pair distribution function. An

attempt has been made in the present work to utilize the X-ray powder

data sets to refine the structure and electron density distribution

using the currently available versatile methods, MEM, multipole

analysis and determination of pair distribution function for these

two systems.

Keywords. Electron density; Si; Ge; X-ray powder data; maximum

entropy method; multipole analysis; pair distribution function.

PACS Nos 61.00; 61.10.Nz; 61.10.-i