the inelastic current is needed to taken into account if the channel is short

[njuxyh]

Hi all:
I have the question is because as I know in a short channel in devices, i.e under the electron mean free path about 1 um, the electron transport belongs ballistic transport, the electron-phonon coupling can be omitted. is there any necessity to take the inelastic current into account?

if we consider the temperature effect on the transport properties? it is necessary to take the inelastic current into account although the short channel about 1nm?

please help me make this concept clear.
thanks very much?



 

[Daniele Stradi]

Hi,

Yes, temperature effects might still be important and affect the transport through the device, see, e.g., the cases treated in:

First-principles electron transport with phonon coupling: Large scale at low cost
Tue Gunst, Troels Markussen, Mattias L. N. Palsgaard, Kurt Stokbro, and Mads Brandbyge Phys. Rev. B 96, 161404(R)
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.161404

Best regards,
Daniele

[njuxyh]

 thank you for your reply.
i noted the paper you mentioned in that reference, the PN junction is about the 10 plus nm.
and my current device, the channel is the only 3nm, so may i ask it is necessary to take the EPC account ?

[Daniele Stradi]

That really depends on the electronic structure of the device throughout the channel. It is difficult to say anything without having done the actual calculation.

If you find that the current through the device is particularly small, then inelastic effects might be important.

Best,
Daniele

[njuxyh]

thank you for your reply.
i have a question if i consider EPC effect into my short device. and found the current increase.(maybe it is natural).
but it is unreasonable in physics because the channel is short, the ballistic electron like , it has no chance to exchange energy with phonon in reality.
so i am wondering the inelastic current has really meanful?


thanks very much !

[Daniele Stradi]

if we consider the temperature effect on the transport properties? it is necessary to take the inelastic current into account although the short channel about 1nm?

That depends a lot on the type of device and geometry. In the case of e.g. molecular or graphene-like junctions, the effects of electron-phonon coupling can be quite large, even if the actual "channel" is rather short. See e.g. PHYSICAL REVIEW B 93, 245415 (2016).

The best thing is to try to do the actual calculation.

Best,
Daniele