244 research outputs found
Electronic transport properties of (fluorinated) metal phthalocyanine
The magnetic and transport properties of the metal phthalocyanine (MPc) and
FMPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of
molecules in contact with S-Au wires are investigated by density functional
theory within the local density approximation, including local electronic
correlations on the central metal atom. The magnetic moments are found to be
considerably modified under fluorination. In addition, they do not depend
exclusively on the configuration of the outer electronic shell of the central
metal atom (as in isolated MPc and FMPc) but also on the interaction
with the leads. Good agreement between the calculated conductance and
experimental results is obtained. For M = Ag, a high spin filter efficiency and
conductance is observed, giving rise to a potentially high sensitivity for
chemical sensor applications.Comment: 8 pages (two-column), 8 figure
Electronic and optical properties of metal-doped TiO nanotubes: Spintronic and photocatalytic applications
Due to their characteristic geometry, TiO nanotubes (TNTs), suitably
doped by metal-substitution to enhance their photocatalytic properties, have a
high potential for applications such as clean fuel production. In this context,
we present a detailed investigation of the magnetic, electronic, and optical
properties of transition-metal doped TNTs, based on hybrid density functional
theory. In particular, we focus on the , the , as well as selected
transition-metal doped TNTs. Thereby, we are able to explain the enhanced
optical activity and photocatalytic sensitivity observed in various
experiments. We find, for example, that Cr- and W-doped TNTs can be employed
for applications like water splitting and carbon dioxide reduction, and for
spintronic devices. The best candidate for water splitting is Fe-doped TNT, in
agreement with experimental observations. In addition, our findings provide
valuable hints for future experimental studies of the ferromagnetic/spintronic
behavior of metal-doped titania nanotubes.Comment: 25 pages (preprint style), 10 figure
Magnetic, electronic and vibrational properties of metal and fluorinated metal phthalocyanines
The magnetic and electronic properties of metal phthalocyanines (MPc) and
fluorinated metal phthalocyanines (FMPc) are studied by means of spin
density functional theory (SDFT). Several metals (M) such as Ca, all first
d-row transition metals and Ag are investigated. By considering different open
shell transition metals it is possible to tune the electronic properties of
MPc, in particular the electronic molecular gap and total magnetic moment.
Besides assigning the structural and electronic properties of MPc and
FMPc, the vibrational modes analysis of the ScPc\textendash ZnPc series
have been studied and correlated to experimental measurements when available.Comment: 28 pages (preprint style), several figure
Students' Reluctance to Attend Office Hours: Reasons and Suggested Solutions
This paper focuses on investigating students’ reasons for their reluctance to attend faculty members’ office hours. Study participants included 500 male and female students from the Colleges of Engineering (n = 248) and Arts and Social Sciences (CASS) (n = 252) at Sultan Qaboos University (SQU). The study followed a descriptive-analytical approach, and a questionnaire was utilized to collect people’s views. The results of the study indicate that the rates of SQU students’ attendance to office hours were low, and some students (11.2%) do not attend at all as they consider these office hours a waste of time. The main reasons behind the students’ lack of interest in office hours were busy student timetables, conflicts between faculty office hours and students’ timetables, and easier and faster ways of getting information than visiting faculty members. Additional reasons were related to faculty members’ personalities and their discouraging attitudes toward attending office hours. The researchers recommend that SQU adopt a new strategy for encouraging faculty members to hold office hours, familiarizing students with the importance of office hours and assigning part of a course’s grades to meeting with faculty members’ office hours
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