Author Topic: current calculation  (Read 3499 times)

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Offline Dipankar Saha

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current calculation
« on: February 9, 2016, 12:24 »
Hello,

For a 2D sheet.... how do you consider the dimensions while calculating current? From transmission analyzer we get some value e.g. 530 nA, 1200 nA etc.  ...but not something like micro_A/ micro_m (as shown in http://in4.iue.tuwien.ac.at/pdfs/sispad2013/19-1.pdf) !!

N.B.:-
  "L" is fine.... But, as it's a flake...width should be periodic...

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Dipankar

Offline Jess Wellendorff

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Re: current calculation
« Reply #1 on: February 10, 2016, 09:49 »
You should divide the current by the width of the 2D sheet in the periodic direction that is not the transport direction, i.e. divide by the length along A or B.

Offline Dipankar Saha

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Re: current calculation
« Reply #2 on: February 10, 2016, 11:02 »
Thank you Jess... :)
« Last Edit: February 10, 2016, 13:47 by Dipankar Saha »

Offline Dipankar Saha

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Re: current calculation
« Reply #3 on: February 10, 2016, 13:57 »
However_
are you sure we need to divide it by 'W' (width) ? / Because, the expression that we use to get current in such cases....has the only term which relates with dimensionality   is the DOS.../ You know that whether it's   DOS or  n(r) ... the unit is " /cm3 " {Regardless of the fact that it's a 2D material....}

Best_
Dipankar

Offline Jess Wellendorff

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Re: current calculation
« Reply #4 on: February 10, 2016, 14:37 »
I'm not sure what you are getting at, but let me say this: If you have a device configuration with a graphene 2D sheet that is periodic along B, has vacuum along A, and has C as its transport direction, it is very reasonable to divide the current with the width of the sheet along B.

Why is this? An example: Let's say you have run the calculation, and the current is 500 nA. However, your graphene sheet is in principle infinite along B. Does this mean that the current through a macroscopic graphene sheet is 500 nA * inf = inf ? No, that clearly makes no sense. Truly infinite 2D sheets do not exist. Much better then to think of an intrinsic property such as current density: 500 nA/0.5 nm = 1000 nA/nm.