excitons{ }

Calling sequence

quantum{ region{ excitons{ } } }

Properties

• usage: $\mathrm{optional}$

• items: maximum 1

Functionality

An optional group triggering computation of binding energies of excitons.

Note

This feature is under development.

Attention

This model can be used only for 1D simulations.

Nested keywords

electron_mass hole_mass density_averaged_masses dielectric_const energy_cutoff accuracy

---

electron_mass

Calling sequence

quantum{ region{ excitons{ electron_mass = ... } } }

Properties

• usage: $\mathrm{optional}$

• type: real number

• values: ${10}^{-3}\le r\le 10.0$

• default: volume average of values from the material database

• unit: $-$

Functionality

Effective mass of electron involved in the exciton.

---

hole_mass

Calling sequence

quantum{ region{ excitons{ hole_mass = ... } } }

Properties

• usage: $\mathrm{optional}$

• type: real number

• values: ${10}^{-3}\le r\le 10.0$

• default: volume average of values from the material database

• unit: $-$

Functionality

Effective mass of hole involved in the exciton.

---

density_averaged_masses

Calling sequence

quantum{ region{ excitons{ density_averaged_masses = ... } } }

Properties

• usage: $\mathrm{optional}$

• type: choice

• values: yes or no

• default: no

Functionality

Effective masses of hole and electron are averaged with weights taken from probability densities of related states

---

dielectric_const

Calling sequence

quantum{ region{ excitons{ dielectric_const = ... } } }

Properties

• usage: $\mathrm{optional}$

• type: real number

• values: $1.0\le r\le {10}^3$

• default: volume average of values from the material database

• unit: $-$

Functionality

Effective dielectric constant assumed for electron-hole Coulomb interaction; If no explicit value of the dielectric constant is set, then the material values of the static dielectric constant (as given by the database and used in Poisson equation) are volume-averaged over the quantum region

---

energy_cutoff

Calling sequence

quantum{ region{ excitons{ energy_cutoff = ... } } }

Properties

• usage: $\mathrm{required}$

• type: real number

• values: [1e-3, ...)

• unit: $\mathrm{eV}$

Functionality

Maximum energy difference of electron and hole states involved in forming exciton

---

accuracy

Calling sequence

quantum{ region{ excitons{ accuracy = ... } } }

Properties

• usage: $\mathrm{optional}$

• type: real number

• values: ${10}^{-10}\le r\le 0.1$

• default: $r=1e-4$

• unit: $-$

Functionality

Accuracy used in minimisation procedure to compute the exciton binding energy

---

Last update: 17/04/2025