Magnetism versus band-gap relationship in diluted magnetic semiconductors: megatom impurity behavior of the magnetic dopant complexes

Abstract

An analysis of ab initio numerical results obtained for the total energy of diluted magnetic semiconductors (DMSs) doped with dopant formations of various structural and spin conformations consisting of 2–4 3D transition metal (TM atoms) has revealed that a dopant formation acts as large impurity atom i.e., as a megatom, in a reverse analogy to the process of the adsorption of sp-atoms onto metallic surfaces. As a result, the d-orbitals of the magnetic dopant formation (the megatom) become hybridized with the sp-bands of the host anions thus creating a number of impurity states which are reflected in the changes of the band gap of the DMS establishing an implicit relationship between the band gap and magnetism. Additional findings also indicate that: (i) the total magnetic moment M tot ( α ) and the band gap e gap ( α ) which characterize a DMS with a dopant formation in spin conformation (α) do not vary independently from each other but instead form one composite system parameter. (ii) The per dopant-pair magnetic interactions in dopant formations consisting of more than two dopants are smaller than those obtained for an isolated dopant-pair. These are demonstrated with results obtained for GaN doped with 3D-TM dopant formations.

Improving the magnetic moment of Ca2Ge and promoting the conversion of semiconductors to diluted magnetic semiconductors using Mn-doping

“…Therefore, semi-metallic materials are preferred materials for manufacturing magnetic ionimplanted DMS electronic devices. [4][5][6][7][8] Recently, investigations of DMS have mainly focused on III-V, IV, II-VI, oxide and sulde semiconductors, such as GaAs, GaN, Si, Ge, ZnO, MoS 2 , etc. [9][10][11][12][13] The preparation of DMS mainly uses transition metal atoms or rare earth ions, which have spin magnetic moment, doped to substitute some atoms in the semiconductor material.…”

A Reference Source Circuit Design for Voltage Controlled Oscillator Chips

“…e second one is to improve the PSRR [11,12]. During the operation of a voltage controlled oscillator, a large number of high-frequency noises are produced by the switching and breaking of the switch tube.…”