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qcl:advanced_settings [2022/02/23 18:10] thomas.grange [Contributions of individual scattering processes] |
qcl:advanced_settings [2022/03/30 16:36] (current) thomas.grange [Definition of graded alloy and graded interfaces] |
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| ==== Parallelization ==== | ==== Parallelization ==== | ||
| + | |||
| + | === Number of threads === | ||
| + | |||
| The number of threads can be controlled using the command <Maximum_Number_of_Threads> | The number of threads can be controlled using the command <Maximum_Number_of_Threads> | ||
| Line 12: | Line 15: | ||
| </code> | </code> | ||
| - | For optimal performances, we recommended that <Maximum_Number_of_Threads> does not exceed the number of **physical** cores (when hyperthreading is activated, the number of physical cores is half the one on logical processsors). | + | For an automatic setting, use 0 or do not specify this command. In this case, the number of threads will be set to half of the number of physical cores. |
| + | |||
| + | In any case, we recommended that <Maximum_Number_of_Threads> does not exceed the number of **physical** cores (note that when hyperthreading is activated, the number of physical cores is half the one on logical processsors). | ||
| === Parallelization in case of combined Temperature-Voltage sweep === | === Parallelization in case of combined Temperature-Voltage sweep === | ||
| Line 36: | Line 41: | ||
| In this example, the total number of threads will be <Threads>* <Maximum_Number_of_Threads> = 6*2 = 12. | In this example, the total number of threads will be <Threads>* <Maximum_Number_of_Threads> = 6*2 = 12. | ||
| + | |||
| + | ==== Definition of graded alloy and graded interfaces ==== | ||
| + | |||
| + | There are two possibilities to define graded alloy profile. | ||
| + | |||
| + | === Linearly graded alloys === | ||
| + | To define a linear graded alloy profile, two materials first need to be defined in the ''<Material>'' section | ||
| + | For example, | ||
| + | <code> | ||
| + | <Material> | ||
| + | <Name>GaAs</Name> <!-- Binary material --> | ||
| + | <Alias>mat1</Alias> | ||
| + | <Effective_mass_from_kp_parameters>yes</Effective_mass_from_kp_parameters> | ||
| + | </Material> | ||
| + | |||
| + | <Material> | ||
| + | <Name>Al(x)Ga(1-x)As</Name> <!-- Ternary material --> | ||
| + | <Alloy_Composition>0.15</Alloy_Composition> <!-- alloy composition x --> | ||
| + | <Alias>mat2</Alias> | ||
| + | <Effective_mass_from_kp_parameters>yes</Effective_mass_from_kp_parameters> | ||
| + | </Material> | ||
| + | </code> | ||
| + | |||
| + | Then, in the layer definition (named ''<Superlattice>''), the following can be used to define a layer with a linear alloy profile, with composition starting from the material "mat1" and ending with the material "mat2" composition. | ||
| + | <code> | ||
| + | <Layer> <!-- all the material parameters will be linearily interpolated between <Material1> and <Material2> --> | ||
| + | <Material1>mat1</Material1> | ||
| + | <Material2>mat2</Material2> | ||
| + | <Thickness unit="nm">5.0</Thickness> | ||
| + | </Layer> | ||
| + | </code> | ||
| + | |||
| + | |||
| + | === Graded interfaces === | ||
| + | |||
| + | To specify a grading for all the interfaces of the structure, the following command ''<InterfaceWidth>'' has to be included in the ''<Interface_Roughness>'' section. | ||
| + | <code> | ||
| + | <Interface_Roughness> | ||
| + | <InterfaceWidth unit="nm">0.8</InterfaceWidth> | ||
| + | ... | ||
| + | </Interface_Roughness> | ||
| + | </code> | ||
| + | In this case, the alloy profile of the all strucure is convoluted by a Gaussian. For a well defined interface, this results in an error function profile of the form: | ||
| + | $$ | ||
| + | c(z) = c_0 + d_0 \text{erf} \left[2 | ||
| + | \sqrt{ln(2)}(z − z_0)/L \right] | ||
| + | $$ | ||
| + | where $L$ is the quantity specified in ''<InterfaceWidth>''. | ||
| ==== Scattering processes ==== | ==== Scattering processes ==== | ||
qcl/advanced_settings.1645639833.txt.gz · Last modified: 2022/02/23 18:10 by thomas.grange
