Dear Kwant developer, Thank you for your effort in developing Kwant. I have a question about the definition of the direction of momentum in the smatrix.lead_info. Assume a lead lies along the y direction with primitive vector (0,1). The symmetry operation of a lead is (0,1) if the lead goes towards the positive direction and is (0,1) if the lead goes towards the negative direction. For the momenta contained in smatrix.lead_info for these two leads , do they use the same coordinate system? Positive momenta mean the direction (0,1), negative momenta mean the direction (0,1). For velocity, in smatrix.lead_info, it has nothing to do with the coordinate system. Positive means outgoing, negative means incoming in the lead. Thank you KS Chan
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Dear KS Chan,
The lead momenta, just like lead velocities are the lattice momenta and have in general no relation with the coordinate system. The wave function is proportional to the exp(i k n), with n the number of the lead unit cell and k the momentum.
I hope that helps, Anton
On Thu, Mar 9, 2017 at 8:53 AM, Prof. CHAN Kwok Sum apkschan@cityu.edu.hk wrote:
Dear Kwant developer,
Thank you for your effort in developing Kwant.
I have a question about the definition of the direction of momentum in the smatrix.lead_info. Assume a lead lies along the y direction with primitive vector (0,1). The symmetry operation of a lead is (0,1) if the lead goes towards the positive direction and is (0,1) if the lead goes towards the negative direction. For the momenta contained in smatrix.lead_info for these two leads , do they use the same coordinate system? Positive momenta mean the direction (0,1), negative momenta mean the direction (0,1). For velocity, in smatrix.lead_info, it has nothing to do with the coordinate system. Positive means outgoing, negative means incoming in the lead.
Thank you
KS Chan
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Dear Anton, I note that when there is a magnetic field in the lead, the momenta depends on the position of the lead. Is my observation correct? I guess it is related to the algorithm used in finding the momenta of the modes with a fixed energy. Am I right? With regards, KS Chan
On 12/3/2017, 11:47 PM, "anton.akhmerov@gmail.com on behalf of Anton Akhmerov" <anton.akhmerov@gmail.com on behalf of anton.akhmerov+kd@gmail.com> wrote:
Dear KS Chan,
The lead momenta, just like lead velocities are the lattice momenta and have in general no relation with the coordinate system. The wave function is proportional to the exp(i k n), with n the number of the lead unit cell and k the momentum.
I hope that helps, Anton
On Thu, Mar 9, 2017 at 8:53 AM, Prof. CHAN Kwok Sum apkschan@cityu.edu.hk wrote: > Dear Kwant developer, > > Thank you for your effort in developing Kwant. > > I have a question about the definition of the direction of momentum in the > smatrix.lead_info. Assume a lead lies along the y direction with primitive > vector (0,1). The symmetry operation of a lead is (0,1) if the lead goes > towards the positive direction and is (0,1) if the lead goes towards the > negative direction. For the momenta contained in smatrix.lead_info for these > two leads , do they use the same coordinate system? Positive momenta mean > the direction (0,1), negative momenta mean the direction (0,1). For > velocity, in smatrix.lead_info, it has nothing to do with the coordinate > system. Positive means outgoing, negative means incoming in the lead. > > Thank you > > KS Chan > > > > Disclaimer: This email (including any attachments) is for the use of the > intended recipient only and may contain confidential information and/or > copyright material. If you are not the intended recipient, please notify the > sender immediately and delete this email and all copies from your system. > Any unauthorized use, disclosure, reproduction, copying, distribution, or > other form of unauthorized dissemination of the contents is expressly > prohibited.
Disclaimer: This email (including any attachments) is for the use of the intended recipient only and may contain confidential information and/or copyright material. If you are not the intended recipient, please notify the sender immediately and delete this email and all copies from your system. Any unauthorized use, disclosure, reproduction, copying, distribution, or other form of unauthorized dissemination of the contents is expressly prohibited.
Dear Chan,
The momenta do not depend on the position of the lead. Did you check that your gauge is translational invariant and has the symmetry of the lead ? There is a warning on this in the Kwant documentation.
Adel
On Tue, Sep 19, 2017 at 7:22 PM, Prof. CHAN Kwok Sum apkschan@cityu.edu.hk wrote:
Dear Anton, I note that when there is a magnetic field in the lead, the momenta depends on the position of the lead. Is my observation correct? I guess it is related to the algorithm used in finding the momenta of the modes with a fixed energy. Am I right? With regards, KS Chan
On 12/3/2017, 11:47 PM, "anton.akhmerov@gmail.com on behalf of Anton Akhmerov" <anton.akhmerov@gmail.com on behalf of anton.akhmerov+kd@gmail.com> wrote:
Dear KS Chan, The lead momenta, just like lead velocities are the lattice momenta and have in general no relation with the coordinate system. The wave function is proportional to the exp(i k n), with n the number of the lead unit cell and k the momentum. I hope that helps, Anton On Thu, Mar 9, 2017 at 8:53 AM, Prof. CHAN Kwok Sum <apkschan@cityu.edu.hk> wrote: > Dear Kwant developer, > > Thank you for your effort in developing Kwant. > > I have a question about the definition of the direction of momentum
in the > smatrix.lead_info. Assume a lead lies along the y direction with primitive > vector (0,1). The symmetry operation of a lead is (0,1) if the lead goes > towards the positive direction and is (0,1) if the lead goes towards the > negative direction. For the momenta contained in smatrix.lead_info for these > two leads , do they use the same coordinate system? Positive momenta mean > the direction (0,1), negative momenta mean the direction (0,1). For > velocity, in smatrix.lead_info, it has nothing to do with the coordinate > system. Positive means outgoing, negative means incoming in the lead. > > Thank you > > KS Chan > > > > Disclaimer: This email (including any attachments) is for the use of the > intended recipient only and may contain confidential information and/or > copyright material. If you are not the intended recipient, please notify the > sender immediately and delete this email and all copies from your system. > Any unauthorized use, disclosure, reproduction, copying, distribution, or > other form of unauthorized dissemination of the contents is expressly > prohibited.
Disclaimer: This email (including any attachments) is for the use of the intended recipient only and may contain confidential information and/or copyright material. If you are not the intended recipient, please notify the sender immediately and delete this email and all copies from your system. Any unauthorized use, disclosure, reproduction, copying, distribution, or other form of unauthorized dissemination of the contents is expressly prohibited.
participants (3)

Abbout Adel

Anton Akhmerov

Prof. CHAN Kwok Sum