Direct observation of confined acoustic phonon polarization branches in free-standing semiconductor nanowires
Research team led by SHINES PI Prof. Balandin at UC Riverside discover new method to dissipate heat in electronic devices by modulating the flow of phonons (elemental excitations) through semiconductor nanowires. They report results of Brillouin—Mandelstam light scattering spectroscopy, which reveal multiple (up to ten) confined acoustic phonon polarization branches in GaAs nanowires with a diameter as large as 128 nm, at a length scale that exceeds the grey phonon mean-free path in this material by almost an order-of-magnitude. The dispersion modification and energy scaling with diameter in individual nanowires are in excellent agreement with theory. The phonon confinement effects result in a decrease in the phonon group velocity along the nanowire axis and changes in the phonon density of states. The obtained results can lead to more efficient nanoscale control of acoustic phonons, with benefits for nanoelectronic, thermoelectric and spintronic devices.
This work is published in Nature Communication.
Oct.31 to Nov.4 2016
SHINES talks for symposium titled “Topological Insulator/ Ferromagnet Heterostrctures for spintronics” at MMM Conference 2016.
Three SHINES PIs; Prof. Jing Shi, Prof. Kang L. Wang and Mingzhong Wu gave invited talks for the symposium titled “Topological Insulator/ Ferromagnet Heterostrctures for spintronics” at MMM 2016 held in New Orleans-Louisiana.
Prof. Shi’s talk is “Enhanced spin Seebeck effect in topological insulator/ magnetic insulator heterostructures”
Prof. Wang’s talk is “Topological Insulator/Ferromagnet Heterostructures for Spintronics”
Prof. Wu’s talk is “Photo-Spin-Voltaic Effect”
SHINES Research Highlighted by the US Department of Energy
In May, the newsletter of the DOE Office of Science described recent results obtained by the Balandin Group showing acoustic phonon confinement effects in nanoporous arrays. Understanding changes in the acoustic phonon spectrum induced by spatial confinement is important for the fine-tuning of heat propagation in nanometer scale structures and electronic devices. Investigation of the acoustic phonons was made possible by development of the Brillouin-Mandelstam spectroscopy tool at UC Riverside. Fariborz Kargar (pictured to the left) – Research Assistant and PhD Candidate in Balandin group – was the first author of the paper published in Applied Physics Letters.
Congressman Mark Takano visits Device Discovery Lab
On March 11th, US Congressman Mark Takano (41st district) visited Professor Khitun's Device Discovery Lab and had a thirty minute discussion about the ongoing research on magnonic holographic imaging of magnetic nanostructures. This work is supported by the SHINES center and director Professor Jing Shi.
Shi Group Research Profiled by UCR Today
A team of researchers, led by Jing Shi's group at UC Riverside, have demonstrated for the first time the transmission of electrical signals through insulators in a sandwich-like structure, a development that could help create more energy efficient electronic devices.
Dr. Elaine Li's research on ultrafast processes in atomically thin materials has been profiled by the UT Austin College of Natural Sciences. In October 2015, Dr. Li was elected to the American Physical Society.
Dr. Alexander Balandin, UC Presidential Chair Professor of Electrical and Computer Engineering is among the five UC Riverside professors included in the Most Influential Scientists list published by the Thomson Reuters. The Thomson Reuters Highly Cited Researchers list is published annually based on the number of citations in several categories. Dr. Balandin was selected in the Physics category.
Professor Jing Shi has been spotlighted in UCR's "Living the Promise" series focusing on breakthrough research. Professor Shi's lab focuses on fundamental problems associated with how to generate, conserve and save energy. Their focus is on spin and heat, specifically in trying to leverage the spin degree of freedom in electrons to convert other forms of energy into electricity, such as heat, more efficiently.
David Ellsworth of Mingzhong Wu's lab at CSU was a finalist for the Best Student Presentation Award at the 13th Joint MMM-Intermag Conference.
David Ellsworth of Mingzhong Wu's lab at CSU won the Best Poster Award at the 2015 Front Range Advanced Magnetics Symposium.
Professor Chia-Ling Chien has been awarded the 2015 IUPAP Magnetism Award and Néel Medal for pioneering discoveries in magnetic materials and nanostructures.
- The 11th International Nanotechnology Conference on Communication and Cooperation
- May 11-13, 2015 / Hilton Fukuoka Sea Hawk, Fukuoka, Japan
- Graduate Student’s Chi Tang and Aleksey Volodchenkov from UC Riverside, have been invited to present a poster and represent SHINES EFRC at this year’s conference.