New forms of carbon break the record of density and predicted to possess tunable electronic properties
Stony Brook University graduate student Qiang Zhu, together with Professor of Geosciences and Physics, Artem R. Oganov, postdoc Andriy O. Lyakhov and their colleagues from the University de Oviedo in Spain, have predicted three new forms of carbon, the findings of which were published in a paper entitled “Denser than diamond: Ab initio search for superdense carbon allotropes,” in the June 7, 2011 online edition of Physical Review B. So far, each new found modification of carbon resulted in a scientific, technological revolution – the same could happen now, if scientists can find a way to synthesize these new forms of carbon.
Elemental carbon possesses a unique range of structures and properties – from ultrasoft graphite to superhard diamond, including elusive carbines, beautifully symmetric fullerenes, carbon nanotubes, and the recently established new form, M-carbon (the structure of which was predicted by Oganov in 2006). Properties of all these modifications of carbon are so interesting and so tunable that two Nobel prizes were awarded recently for their studies (the 1996 Chemistry and 2010 Physics awards).
Graphene is the densest two-dimensional material, with unique mechanical and electronic properties and having some electrons moving with near-light velocities and behaving as if they had zero mass. Diamond has set several records – it is not only the hardest known material, but also has denser packing of atoms than any other known three-dimensional material. When doped by boron, diamond displays superconductivity and is the only known material simultaneously displaying superhardness and superconductivity.
Now Zhu, Oganov, and their colleagues propose three new structures of carbon, which should be more than 3% denser than diamond. Greater density means that electrons should have a higher kinetic energy (that is, move faster). Calculations of Zhu et al. show that the new modifications are almost as hard as diamond, but do not exceed its hardness. Their electronic properties are very diverse, with the band gap ranging from 3.0 eV to 7.3 eV. Band gap is the minimum separation in energy between occupied and unoccupied electronic orbitals and is the most important characteristic of the electronic structure of materials. Such a wide range of band gaps implies the possibility of tuning the electronic properties. The band gap of 7.3 eV predicted for the tP12 modification is the largest value for all forms of carbon.
Other interesting properties include ultralow compressibility – when subjected to pressure, the new forms of carbon will contract less than most materials (even slightly less than diamond, the current record holder). They have higher refractive indices and stronger light dispersion than diamond – which means better brilliance and color effects than those displayed by diamond. “Carbon is an inexhaustible element in its chemical diversity and in the multitude of its physical applications”, says Professor Oganov. “If these predicted forms of carbon can be synthesized, they may find important technological roles”. Researchers believe that the new forms of carbon, thanks to their high densities, could be synthesized by shock compression of low-density modifications, or by directed growth on substrate.
Yi-Xian Qin of Biomedical Engineering Elected Into American Institute for Medical and Biological Engineering’s (AIMBE) College of Fellows
Yi-Xian Qin, Ph.D., Professor of Biomedical Engineering, Orthopaedics, and Biophysics at Stony Brook University, has been elected into the American Institute for Medical and Biological Engineering’s (AIMBE) College of Fellows. Recipients of this honor, considered one of the highest in the biomedical engineering discipline, are chosen for their outstanding achievements in medical and biological engineering.
AIMBE states that Dr. Qin was elected into the College of Fellows “for his work in orthopedic biomechanics, which has provided unique insights into the mechanical control of bone repair and remodeling, as well as noninvasive diagnosis of bone diseases.”
Dr. Qin, Director of Stony Brook’s Orthopaedic Bioengineering Research Laboratory, has developed a new form of ultrasound that assesses multiple parameters of hard tissue like bone. This technology, called SCAN (Scanning Confocal Acoustic Navigation) is more advanced than existing ultrasound in that it assesses bone parameters beyond mineral density.
“SCAN enables researchers to identify weak regions in bone and thus is an emerging technology that may assist in bone healing and prediction of fractures,” says Dr. Qin. “The technology also has the potential as a diagnostic for the prediction of early bone loss, a hallmark of osteoporosis, a disease that affects millions worldwide.”
The 2011 AIMBE election of Fellows led to 79 researchers nationwide named as Fellows. A non-profit organization representing 50,000 individuals, AIMBE was founded in 1991 to provide leadership and advocacy in medical and biological engineering for the benefit of society. The College of Fellows is comprised of the top 2 percent of medical and biological engineers.
Thomas C. Skalak, AIMBE President and Vice President for Research at the University of Virginia, called the 2011 elected Fellows talented individuals who “truly enhance the fabric of our society.”
Recognized for their contributions in teaching, research, and innovation, Fellows include leaders in industry as entrepreneurs, directors of research and development, and respected professors as well as heads of engineering and medical schools nationwide.
Dr. Qin received his Ph.D. in Mechanical Engineering from Stony Brook University in 1997. He earned an M.S. in Mechanical Engineering in 1993, also from Stony Brook University. Previous to that he completed his undergraduate education in Shanghai, China, in 1982.
President Samuel L. Stanley Jr., MD, today applauded Governor Andrew Cuomo and SUNY Chancellor Nancy Zimpher’s announcement of the NYSUNY 2020 Program.
“NYSUNY 2020 is exciting for SUNY, for Stony Brook University and for our region,” said President Stanley. “We applaud Governor Cuomo for his leadership and Chancellor Nancy Zimpher as well, for her commitment and support; together they are advancing the role of SUNY’s research institutions and the future of the State’s prospects for economic development.
“The Governor’s plan calls for an infusion of capital dollars for construction keyed to research and requires long term economic and academic plans which Stony Brook has finalized recently and will promptly submit for consideration,” said Dr. Stanley. “This visionary plan presents the opportunity for Stony Brook to increase tuition resulting in additional operating revenue while helping us generate the necessary private funding that will enable us to populate new facilities with leading research faculty and staff, and provide opportunities for the most exceptional students. In so doing, the plan will further our mission of education, research, and discovery of cutting edge technology and new medical treatments.
“As a top-tier research university and member of the prestigious AAU, Stony Brook University is poised to be the engine of a dynamic, interconnected and entrepreneurial regional network for economic innovation and will help NY excel under NYSUNY 2020. SBU accounts for 97% of all SUNY royalties; its average royalty income is $10 million – $15 million per year, and SBU’s gross royalty income for FY 09 was $17,220,322.57. In addition, SBU researchers have filed approximately 1,400 invention disclosures and have been awarded more than 800 patents.
“It is exceptional that the Governor and the Chancellor have recognized the track record of Stony Brook and the other University Centers for their leadership and ability to have a positive and productive impact on regional economic development. We look forward to working with the entire Long Island delegation, the Long Island Association and other key business leaders on Long Island to get their full support, which is critical for NYSUNY 2020 to succeed.
News Release from Gov. Cuomo’s Office: GOVERNOR CUOMO AND SUNY CHANCELLOR ZIMPHER UNVEIL GROUNDBREAKING “NYSUNY 2020″ PROGRAM