K.p theory model & Heavy-hole effective masses in strained QWs

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Discussion Overview

The discussion revolves around the k.p theory model and the effective masses of heavy and light holes in strained quantum wells (QWs). Participants explore the implications of strain on effective mass and subband states, as well as seek guidance on computational methods for modeling these phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • Paul M. inquires about models in Mathcad or Mathematica for calculating band diagrams and wave functions in strained multi-quantum well (MQW) structures, expressing a lack of experience in coding.
  • Paul M. also asks how to calculate the effective masses of strained heavy and light holes.
  • One participant provides a reference link that may contain useful information related to the topic.
  • Another participant suggests obtaining the book "Physics of Optoelectronic Devices" by S. L. Chuang for foundational knowledge, although it may not provide direct coding guidance.
  • Khai mentions working with an 8-band k.p method for band structure calculations and describes difficulties in solving coupled differential equations from a 2-band k.p model.
  • Khai seeks help with the finite difference method to solve the equations and references a specific page in Chuang's book for guidance.
  • Khai reports success with the 2-band model but encounters spurious solutions in the 8-band model as per a cited article, questioning the correct arrangement of wave functions in the code.
  • Another participant notes that spurious bands are common when inverting k.p matrices and suggests that there are solutions available to address this issue.

Areas of Agreement / Disagreement

Participants express various approaches and challenges related to k.p theory and computational modeling, but there is no consensus on specific methods or solutions to the problems raised.

Contextual Notes

Participants mention specific references and methods, but there are unresolved mathematical steps and dependencies on definitions that may affect the discussion.

paula1980
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Hi Everyone, :smile:

I am new to the Physics Forums. I have a question regarding k.p theory.

I am keen to design band-diagram, wave-functions of a strained MQW structure. I understand that in strained QWs, Heavy-Hole (and probably light-hole also) effective mass decreases significantly with strain, which consequently affects the subband states in the Hole QW.

Couple of questions I have regarding this are as follows:

1) Does anyone has a model on Mathcad or Mathematica which calculates this? If not can anyone suggest a paper which provides simplified details of how to write the code for this. Unfortunately I am very new to designing field with limited experience in writing code.

2) How can one calculate the strained Heavy and light hole effective masses?

Thanks a million for your help!

Paul M. :smile:
ps: I put this message also in the "Beyond the Standard Model" section as I wasnt sure where my question was best to ask...
 
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Not exactly what you're looking for, but may have some useful references: http://www.sst.nrel.gov/images/MRS98-ES%20of%20Quantum%20Dots.pdf
 
Last edited by a moderator:
Try getting the book, Physics of Optoelectronic Devices by S L Chuang. THe first couple of chapters will provide much of what you are looking for, maybe not the code, but you cna figure it out from there.
 
Hello,

I also try to dealing with 8-band k.p method for bandstructure calculations. First of all, for simple case I am just working on only 2 bands to determine the valance bandstructure of quantum well (from Shun Lien CHuang's book: Physics of Optoelectronic devices at page 182). I met a difficulty from solving the coupled differential equation generated from this 2-band k.p model as following link:

http://i88.photobucket.com/albums/k177/ajou0611/EigSys.jpg?t=1191804568

Could you help me to solve this equation by Finite difference method?

Thanks in advance,

Khai
 
Last edited:
Finite difference wil help. It will be a bear to get good solutions easily. Look at the references on page 184 an d you should be able to get there.
 
Thanks you for your rapid response !

I was now successful in dealing with 2-band k.p model following the reference at page 184 of S. L. Chuang's book. However, in case of 8-band k.p model in Guobin Liu's article et. al Phys. Rev. B 65, 165220 my code generated some spurious solutions. I couldn't get the wave functions as in the paper. I am wondering how can we rearrange the bands? Should we arrange the band alternatively (Psi11,Psi21,...,Psi81,...,Psi1i,Psi2i,...,Psi8i...Psi1N,Psi2N,...,Psi8N) or successively (Psi11,Psi12,...,Psi1N,Psi21,Psi22,...,Psi2N,...,Psi81,Psi82,...,Psi8N)?

Best wishes,

Khai
 
Last edited:
Spurious bands are a trademark of inverting k.p matricies. There are plenty of solutions out there to eliminate them.
 

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