# ttm parameters

Have anyone worked on Fix TTM command and knows the values of

• C_e = electronic specific heat (energy/(electron*temperature) units)
• rho_e = electronic density (electrons/volume units)

for silicon?

Regards,

Leyla

Have anyone worked on Fix TTM command and knows the values of

C_e = electronic specific heat (energy/(electron*temperature) units)

this should be available in the published literature

rho_e = electronic density (electrons/volume units)

this you should be able to compute yourself after a little bit
of thinking what this represents and what material you have.

axel.

Hi....

Am... I dont think the calculation of the charge density as something
trivial .. One would assume "rho = Q/V" , where Q is the charge and
"V" the volume , if we consider the atomic volume of silicon be
equal to 12 cm^3/mol . and 1 mol = 6.02 x10^23 atoms and if each atom
of silicon have 14 electrons, then:
rho = (14 electrons/atom*1.609*10^-19 C/electron)(6.02*10^23
atoms/mol)(1/12 mol/cm^3) = 113005 C/cm^3 or 7.02333*10^23
electrons/cm^3 one could also consider the free electron density if
we consider only the valency electrons (4 valance electrons for
silicon) , then rho_free_electrons = (4 electrons/atom)(6.02*10^23
atoms/mol)(1/12 mol/cm^3) = 2.00667*10^23 free electrons/cm^3 . The
previous result is assuming that the charge is homogenuos i.e Do not
consider Charge Density Distribution The problem become even more
complicate if one consider the distribution of the charge around the
atom (Quantum Mechanics) .

I have no idea what is the electronic specific heat (never hear of it)
, using my physics intuition I would assume the specfic heat is in
someway related with the vibration of the atoms i.e the density of
sates (DOS) , one could consider specific heat due to the vibration
part (phonons), but also a charge contribution due to electron , and
therefore could be phonon electron interaction ....Imagine the atoms
move due to spring (bonding) , but the bonding is due in part to the
electronic charge of the structure, therefore the vibration (motion of
atoms around the equilibrium) would be affected by the electronic
charge distribution .......

Oscar G.

Paul may wish to comment further.

Steve

Thanks for your reply, Just another question, in ttm command, where can I apply the energy or fluence source to the substrate.(J or J/Area)