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qcl:input_file [2019/06/05 13:48]
thomas.grange [Material definition and parameters]
qcl:input_file [2020/05/21 20:50] (current)
thomas.grange [Simulation parameters]
Line 453: Line 453:
 Note that alloy scattering is only considered for the material specified by <​Material_for_scattering_parameters>​.  ​ Note that alloy scattering is only considered for the material specified by <​Material_for_scattering_parameters>​.  ​
  
 +By default the following alloy squared matrix element for a zinc-blende ternary $A_{x}B_{1-x}C$ is considered:
 +$$ 
 +\vert \langle \alpha,k_0 \vert H_{\text{alloy}} \vert \beta,k_0+k \rangle\vert^2 = \int dz \frac{x(1-x) a^3 \Delta E_c}{4} \vert \phi_{\alpha}(z) \phi_{\beta}(z) \vert^2
 +$$ 
 +where $\Delta E_c$ is the conduction band offset between the binaries $AC$ and $BC$.
 +
 +This squared matrix element can be tuned with respect to the above formula by using the following command (tuning the squared matrix element is equivalent of tuning the scattering rate):
 <​code>​ <​code>​
 +  <​Alloy_scattering>​ yes </​Alloy_scattering>​
 +  <​Tune_Alloy_scattering>​0.5</​Tune_Alloy_scattering>​
  </​Scattering>​  </​Scattering>​
 </​code>​ </​code>​
Line 469: Line 478:
 <​code>​ <​code>​
 <​Tune_Elect_Elect_Scattering_Strength>​yes</​Tune_Elect_Elect_Scattering_Strength>​ <​Tune_Elect_Elect_Scattering_Strength>​yes</​Tune_Elect_Elect_Scattering_Strength>​
-<​Elect_Elect_Scattering_Strength>​1.5</​Elect_Elect_Scattering_Strength> ​( a value of 1.0 gives the normal calculation)+<​Elect_Elect_Scattering_Strength>​1.5</​Elect_Elect_Scattering_Strength>​
 </​code>​ </​code>​
 +A value of 1.0 gives the normal calculation.
 ==== Poisson equation ==== ==== Poisson equation ====
 The electrostatic mean-field interactions (electron-electron and electron-impurities interactions) can be switched on/off by using ''​yes''​ or ''​no''​ in the ''<​Poisson>''​ command. The electrostatic mean-field interactions (electron-electron and electron-impurities interactions) can be switched on/off by using ''​yes''​ or ''​no''​ in the ''<​Poisson>''​ command.
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   * ''​N''​ ==> coherent transport between N+1 periods   * ''​N''​ ==> coherent transport between N+1 periods
 In almost all existing QCL designs, 1 is enough. The user should not change this value. (Larger number are needed for superlattices. In almost all existing QCL designs, 1 is enough. The user should not change this value. (Larger number are needed for superlattices.
 +
 +The coherence length for which self-energies are considered can be further limit by using the following command:
 +<​code>​
 + <​Simulation_Parameter>​
 +<​Coherence_length_in_nm>​50.0</​Coherence_length_in_nm>​
 +...
 +</​Simulation_Parameter>​
 +</​code>​
 +Such limitation will speed up the calculation of the self-energies. On the other hand, this can reduce the accuracy of the scattering processes if this length is below the actual coherence length in the simulated device.
  
  
qcl/input_file.1559742506.txt.gz · Last modified: 2019/06/05 13:48 by thomas.grange