Tag: Materials

Kamal Dhungana Research

Kamal Dhungana Research
Schematic diagram of a fluorinated boron nitride nanotube based spin filter device.

Fluorinated boron nitride nanotube as an ideal spin filter

Advisor: Dr. Ranjit Pati

Understanding the electronic structure and the transport property of nano scale materials is of fundamental importance, since these materials are the ultimate candidates for the future of nano technology. Several nano materials, such as quantum dots, semiconducting nano-wires, and organic molecules, have been explored both theoretically and experimentally as the components of electronic circuitry over the last two decades. Among several interesting nano materials, metal free magnetic nano materials are found to be very enticing due to the presence of magnetism in the absence of magnetic ions. Traditionally, the magnetism comes from partially occupied d and f states in the materials; however, this understanding is not always true since s and p states are found to contribute to the magnetism in the metal free magnetic materials. The main advantage of these materials is their high Curie temperature; as a result, they can be utilized in room temperature spin-electronics (spintronics). Recently, using a first-principles approach, we have demonstrated that the fluorinated boron nitride nanotube (BNNT), which is a metal-free magnetic entity, can be used as an excellent spin filter. All majority spin carriers are almost completely blocked while passing through the fluorinated BNNT channel, allowing only the minority spin carriers to pass. We have shown that the long range ferromagnetic spin ordering in fluorinated BNNTs occurs at a temperature much above room temperature.

For more information, please visit my webpage: http://www.phy.mtu.edu/~kbdhunga

By Kamal B. Dhungana


Kamal B. Dhungana, Ranjit Pati, Fluorinated Boron Nitride Nanotube Quantum Dots: A Spin Filter. J. Am. Chem. Soc., 2014, 136, 11494–11498. 

ZnO Nanotubes feature in “Celebrating 50 Years of Applied Physics Letters”

Images of ZnO Nanotubes are selected as one of the cover images of Applied Physics Letters (APL) highlighted in the APL 50th anniversary celebration website. The related article, “Formation of Single Crystalline ZnO Nanotubes without Catalysts and Templates,” was the most read article in March 2007. The images and article are from Professor Yoke Khin Yap’s research group.

Work on Boron Nitride Nanotubes is Featured in NanotechWeb

Recent work on in-situ probing of individual boron nitride nanotubes by scanning tunneling microscopy (STM) inside a transmission electron microscopy (TEM) system is being featured in NanotechWeb. The research is conducted by Hessam M Ghassemi and Reza S Yassar in the mechanical engineering-engineering mechanics department and Chee Hui Lee and Yoke Khin Yap in the physics department. NanotechWeb notes that BNNTs are unique materials which enable the study of band structure modulation by mechanical straining. “This may lead to rational control of the electrical properties of novel nanostructures in the future,” commented Yoke Yap.

View the NanotechWeb article

On the Road

Researchers from the Multiscale Technologies Institute (MuSTI) gained noticeable attention in the 2011 Materials Research Society Fall Meeting, held Nov. 27 to Dec. 2 in Boston. Professor Yoke Khin Yap (Physics) was the lead organizer of “Symposium AA: Carbon Nanotubes, Graphene, and Related Nanostructures.” This symposium attracted about 450 contributed papers and 22 invited lectures and was the largest symposium of the 47 in the meeting.

View the Tech Today article

Molecular Syringes

A story on “Nanotech: Injections Or Sampling? New ‘Molecular Syringes’ Under Testing” based on Siegfried Höfinger’s research has been picked up by several news outlets, such as Science Newsline TechnologyNanotechnology Now, and ScienceDaily. Höfinger is a research fellow with the Dipartimento di Chimica “G. Ciamician,” Universita di Bologna, and an adjunct assistant professor with the Department of Physics at Michigan Tech. The research involves free energy calculations of membrane insertion of individual carbon nanotubes and carbon nanotube bundles, published as Siegfried Höfinger, Manuel Melle-Franco, Tommaso Gallo, Andrea Cantelli, Matteo Calvaresi, José A.N.F. Gomes, Francesco Zerbetto. A computational analysis of the insertion of carbon nanotubes into cellular membranes. Biomaterials, 2011; DOI: 10.1016/j.biomaterials.2011.06.011

Carbon Nanorods Feature as Journal Cover Image

Vertically-aligned carbon nanorods co-developed by Professor Yoke Khin Yap are being featured on the cover of Carbon (issue 49/8, July 2011). These nanorods contained nitrogen donors and will have enhanced electrical and electrochemical properties as compared to pure carbon nanomaterials. They were self-assembled into vertical arrays as induced by the applied electric fields and the incorporation of polarized isonitrile bonds [–N≡C] during the plasma-enhanced chemical vapor deposition (PECVD) process. This work was conducted in the University of Malaya when Professor Yap was on his sabbatical visit during Jan-May 2009. The related article was published by Ritikos et al. in issue 49/6 (May 2011) of the journal. Carbon is a journal published by Elsevier with an impact factor of 4.5.