QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: jerry on September 16, 2011, 03:21

Title: Three Terminal device
Post by: jerry on September 16, 2011, 03:21

Dear,
    I want to figure out that when a gate electrode is introduced to a three terminal device with positive gate bias, is the energy spectrum elevated or decreased relative to zero gate bias? Thanks very much! The version i use is 11.8 alpha. The boundary condition of poisson solver is Neumann. By the way, i found that the energy spectrum (MPSH for the molecule) of the three terminal device is very different from that of two terminal device without a gate electrode (molecular junction device). For instance, when a gate bias -1V is applied, the MPSH energy spectrum of a molecule is very weird, its lowest orbital can be -700eV. Is this reasonable?

Title: Re: Three Terminal device
Post by: kstokbro on September 16, 2011, 23:53

This could be a bug with the new multigrid solver in 11.8. Can you post your script?

Title: Re: Three Terminal device
Post by: jerry on September 20, 2011, 07:50

Thank you for your reply. By the way, if a negative gate bias is applied, is the energy spectrum of the molecule elevated or declined?

Title: Re: Three Terminal device
Post by: zh on September 21, 2011, 17:09

When a negative gate voltage is applied, the energy spectrum of the molecule in the scattering region will be shifted down.

Please refer to here for more discussions on the gate voltage: http://quantumwise.com/forum/index.php?topic=1030.0

Title: Re: Three Terminal device
Post by: nori on September 21, 2011, 17:32

I think  the energy spectrum of the molecule under a negative gate voltage is elevated because an electron has a negative charge.