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Title: Crystallography and Functional Evolution of Atomically Thin Confined Nanowires
Speaker: Dr. Jeremy Sloan, EPSRC Established Career Fellow, Department of Physics, University of Warwick, Coventry, UK
Time: 10:30AM, April 1, 2019
Location: M253, IOP, CAS
Abstract
Encapsulated nanowires (a.k.a. ‘Extreme Nanowires’) can be as small as a single atom in width and are the smallest one-dimensional materials. Their simplicity and robustness make them ideal platforms for the study of fundamental properties of matter, such as phase transformations and the energetics of confined crystal structure formation. Carbon nanotubes are ideal templates for forming and observing crystalline/non-crystalline transitions and molecular ordering either into chains or discrete species. These materials have tested, and continue to test, the state of the art in electron microscopy (i.e. HRTEM or STEM) investigations and their associated spectroscopies but the extremely small size also lends these materials to ab initio (or a posteriori) theoretical investigations whereby their stability, electronic properties and properties can all be studied. This work is leading to ground-breaking and transformative new studies including the physical realisation of Peierls distortions of 1D chains, novel phonon optics and, most recently, spectacular modification of thermal properties [1,2]. A further recent innovation is the observation and study of confined phase transformations at the smallest volume scale ever attempted (i.e. ~1 nm3), an essential precursor to the determination of the smallest scale that we can write information by the technique of PC-RAM [3,4].
[1] "Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes" J. H. Spencer, J. M. Nesbitt, H. Trewhitt, R. J. Kashtiban, G. R. Bell, V. G. Ivanov, E. Faulques, J. Sloan, D. C. Smith, ACS Nano 8 (2014) 9044–9052.
[2] "Electronic Structure Control of sub-Nanometer 1D SnTe via Nanostructuring within Single-Walled Carbon Nanotubes" A. Vasylenko, S, Marks, J. M. Wynn, P. V. C. Medeiros, Q. M. Ramasse, A. J. Morris, J. Sloan, and D. Quigley, ACS Nano 12 (2018) 6023–6031.
[3] "Confined Crystals of the Smallest Phase-Change Material" C. E. Giusca, V. Stolojan, J. Sloan, F. Börrnert, H. Shiozawa, K. Sader, M. H. Rümmeli, B. Büchner, S. R. P. Silva, Nano Lett. 13 (2013) 4020–4027.
[4] "In Situ Electron Beam Amorphization of Sb2Te3 within Single Walled Carbon Nanotubes" S. R. Marks, K. Morawiec, P. Dłużewski, S. Kret, J. Sloan, Acta Phys. Polon. A, 131 (2017) 1324–1327.
Brief Biography of Professor Jeremy Sloan
Jeremy Sloan obtained a B.Sc. in Chemistry from Hull (1982), an M.Sc. from Binghamton University USA (1990) and a PhD in Materials in 1995 from Cardiff University under Prof. Richard J. D. Tilley. He then joined Inorganic Chemistry Laboratory at the University of Oxford in 1995, initially working with Prof. Malcolm L. H. Green FRS, and during this time discovered ‘Extreme Nanowires’ of 2 x 2 and 3 x 3 atomic layer KI, 1D chains of other metal halides and later semiconductores in single walled nanotubes (SWNTs). Subsequently he moved to the University of Surrey (2005-7), Queen Mary University of London (2007-2008) and is now in the Department of Physics at the University of Warwick (from 2008) where he continues pioneering studies into Extreme Nanowires and, more recently, nano-confided Phase Change Materials (nC-PCMs). His awards include the Royal Society University Research Fellowship (2000-8), the FEI European Microscopy Award (2005); the EPSRC grants 'Molography in Carbon Nanotubes' (2005); ‘Nanostructures by Supercritical Fluid Electrodeposition' (2012) and 'New modelling capability for nC-PCMs’ (2016). In 2018 he was awarded a 5-year EPSRC Established Career Fellowship which has Project Partners in Beijing, Oxford, Vienna, Warsaw and Pau, France. He has co-authored and published 193 papers (Web of Science h-index = 46).