| Summary: | The optical emission of cone-shell quantum structures (CSQS) under vertical electric (<i>F</i>) and magnetic (<i>B</i>) fields is studied by means of simulations. A CSQS has a unique shape, where an electric field induces the transformation of the hole probability density from a disk into a quantum-ring with a tunable radius. The present study addresses the influence of an additional magnetic field. A common description for the influence of a <i>B</i>-field on charge carriers confined in a quantum dot is the Fock-Darwin model, which introduces the angular momentum quantum number <i>l</i> to describe the splitting of the energy levels. For a CSQS with the hole in the quantum ring state, the present simulations demonstrate a <i>B</i>-dependence of the hole energy which substantially deviates from the prediction of the Fock-Darwin model. In particular, the energy of exited states with a hole <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>l</mi><mi>h</mi></msub><mo>></mo></mrow></semantics></math></inline-formula> 0 can become lower than the ground state energy with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>l</mi><mi>h</mi></msub><mo>=</mo></mrow></semantics></math></inline-formula> 0. Because for the lowest-energy state the electron <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>l</mi><mi>e</mi></msub></semantics></math></inline-formula> is always zero, states with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>l</mi><mi>h</mi></msub><mo>></mo></mrow></semantics></math></inline-formula> 0 are optically dark due to selection rules. This allows switching from a bright state (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>l</mi><mi>h</mi></msub><mo>=</mo></mrow></semantics></math></inline-formula> 0) to a dark state (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>l</mi><mi>h</mi></msub><mo>></mo></mrow></semantics></math></inline-formula> 0) or vice versa by changing the strength of the <i>F</i> or <i>B</i> field. This effect can be very interesting for trapping photoexcited charge carriers for a desired time. Furthermore, the influence of the CSQS shape on the fields required for the bright to dark state transition is investigated.
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