("Diamonds are a Boyle's best friend." https://en.wikipedia.org/wiki/Robert_Boyle) Thanks, Gene, for the interesting reports & info. Although the following idea wasn't mentioned in these reports, perhaps it has already been discussed in the literature? Over the past several years, I've been pondering the possibility of using solid lattices of differing isotopes as digital storage devices -- e.g., for permanent ROM storage, at least. However, up until your email, I was having difficulty figuring out how to *read out* these data. Thanks to the differing properties of C12 and C13, it should be possible to arrange patterns of such isotopes on a diamond surface that could essentially "read itself out" -- i.e., produce a train of signals that reliably describe the pattern of C12 and C13 atoms encoded in that surface. I don't know enough physics to be able to calculate how long this data storage would persist. I.e., the quantum barriers to exchanging a C12 with an adjacent C13 might be too low at room temperature. Is there a critical temperature that would enable such isotope patterns to persist? If such patterns can persist, then these patterns could conceivably be made to do all sorts of things, including make phonon "mirrors" that would enable the building of lasers and optical pathways along the surface of the diamond; build *quantum dots*; and, in general, do a lot of the things that we normally associate with semiconductors. Note that the "doping" here involves using a different isotope of carbon rather than a different element. This differential doping should be rather easily done using more-or-less-standard CVD methods. At 11:04 AM 5/29/2016, Eugene Salamin via math-fun wrote:
This is for real.
The heat content of a crystal is mainly due to phonons, quanta of vibration.
Heat conduction is due to the transport of phonons.
Phonons are scattered by inhomogeneities in the lattice, so that thermal conductivity is very sensitive to impurities, such as the random distribution of different mass isotopes.
Diamond is quite a remarkable substance.
Since it is thermodynamically unstable with respect to graphite under ordinary temperature and pressure, its synthesis is tricky.
The preferred technology today is chemical vapor deposition (CVD).
On the other hand, it is just carbon.
I expect that by year 2100, diamond synthesis will have become so cheap that recycling centers will have a bin for diamonds.
I wrote a report on diamond for a class I took on optomechanics at the University of Arizona.
http://fp.optics.arizona.edu/optomech/student%20reports/synopsis/SalaminRepo...