QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: jinylee on December 15, 2014, 14:15

Title: How to get Contact Resistance in ATK
Post by: jinylee on December 15, 2014, 14:15
Dear ATK team,

I have reproduced a recent published paper of Gao et al. (APL Materials, 2, 056105 (2014),  http://dx.doi.org/10.1063/1.4876635)

They calculated contact resistance by the ATK code, as shown in eq. (1), I wonder how to get the contact resistance in ATK code.

I cannot find exact contact resistance but the Transmission coefficient.

Is the transmission coefficient related with the Contact resistance?

And another question is how to figure out the ATK code the contact resistance at 0 V bias.

To my knowledge, dI/dV shows conductance after I-V calculation.

Does the contact resistance mean the dI/dV value at 0 V after successive bias calculation?

If so, I'd like to know how much interval bias is resonable to calculation dI/dV.


Thank you in advance for your answers.
Title: Re: How to get Contact Resistance in ATK
Post by: zh on December 18, 2014, 14:30
In that paper, the authors may calculate the transmission spectra at zero bias voltage and then use the equation (1) to estimate the contact resistance.
The coding of eq.(1) to estimate the contact resistance could be easily implemented. Indeed, you may use the "scipy.integrate" to the integration.

The conductance isn't estimated by dI/dV.  For the calculations of conductance, you may refer to an example in the manual: http://quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.transmissionspectrum.html

Title: Re: How to get Contact Resistance in ATK
Post by: abhi005 on May 15, 2015, 15:29
hi ZH,
i have simulated cnt fet . i got results like Id vs Vgs and Id vs Vds now i want to calculate trans conductane of this fet. HOW can i do that? please reply asap.
Title: Re: How to get Contact Resistance in ATK
Post by: Jess Wellendorff on May 21, 2015, 14:22
In order to get anywhere with this question, you should probably first define what you mean by "trans conductance", and then be very specific in your question. Makes it easier to help.
Title: Re: How to get Contact Resistance in ATK
Post by: Anders Blom on May 21, 2015, 19:56
From the basic definition, transconductance is the change in source-drain current when you apply a (small) gate bias. So if you calculate the I-V curve, add a gate bias, then you basically have the data you need to evaluate the transconductance.