university of manchester physicists
TRANSCRIPT
University of Manchester physicists Konstantin Novoselov, left, and Andre Geim
"for groundbreaking experiments regarding the two-dimensional material graphene"
2010 Nobel Prize in Physics
Graphene Some Properties
Density 0.77 mg/m2 (Seran wrap is about 500,000 mg/m2) About 0.5 nm thick Optical transparency 1-2.3% (97.7% transmission) Colorless 2D breaking strength about 100 x that of Steel Electrical Conductivity slightly better than copper modify over a large range by doping (ie can act like a semiconductor) Electron mobility ~10x higher than that in commercial grade silicone Thermal conductivity >10 times that of copper Impervious to helium At last one example of “semi industrial” production of sheets 70 cm wide
2d hexagonal lattice of Carbon Atoms
4 kg cat 1 meter square graphene “hammock” mass of hammock= mass of one whisker of the cat
Graphene: First Crystalline 2-D material A few applications that may be possible include: Solar panels Touch Screens Flexible Electronics High Frequency Electronics Computers Particle Detectors Super Strong Materials Use in Aircraft, Satellites Fundamental Science excitations in graphene behave like two dimensional Dirac Fermions
... here the electrons behave as though they are massless; they also travel long distances without scattering and have been clocked at speeds about 300 times below the speed of light in vacuum—much higher than the typical speed of electrons in semiconductors. http://www.als.lbl.gov/als/science/sci_archive/144dirac_fermions.html
Dmitri Mendeleev 1834-1907
Henry Moseley 1887-1915
Wolfgang Pauli 1900-1958
All electrons in an atom have unique set of quantum numbers. Proposed 4th quantum number for SPIN
Elements are ordered by atomic number Z Atomic Number is equal to number of protons in the nucleus.
First Periodic Table of elements
Some key scientists in development of Periodic Table of the Elements
Suppose electrons did not follow the Pauli Exclusion Principle (ie they could have the same quantum numbers in an atom) Discuss in you groups: What would be some of the consequences of this?
Periodic Table (Chemist)
Metals
Metals
Periodic Table (Cosmologist)
E. Clementi, D. L. Raimondi, and W. P. Reinhardt (1967), Journal of Chemical Physics, volume 47, page 1300
Calculated Atomic Radii (picometers)
http://chemistry.about.com/library/weekly/aa013103a.htm
n
l
Nobel gases He (1s)2
Ne (1s)2(2s)2(2p)6
Ar (1s)2(2s)2(2p)6(3s)2(3p)6
Etc Chemically Inert
Periodic Table (Quantum Mechanic)
Periodic Table
2
3
0 1
Periodic Table for the quantum mechanic
Periodic Table
1
2 2
3 3
4
5
3
4
4
5
s (l=0) p (l=1)
d (l=2)
f (l=3)
6
7
5
Width of each box is 2(2l+1) combinations of ml and ms for given l
