QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: kaihuang on November 21, 2025, 00:06
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Hi all,
Could anyone clarify the physical meaning of electrode_extension_lengths in the device configuration, and how it influences the calculation results? The manual only states that it is “the desired equivalent electrode extension length of each electrode,” which is not very informative.
In a related forum discussion (https://forum.quantumatk.com/index.php?topic=10735.0), it was mentioned that the calculation results depend on this parameter. What is the underlying theory for this dependence?
We already have the parameter equivalent_electrode_lengths, which defines how much of the central region should be equivalent to the electrodes which is clear. But how is electrode_extension_lengths fundamentally different?
In older versions of the manual and ATK (e.g., https://docs.quantumatk.com/tutorials/atk_transport_calculations/atk_transport_calculations.html), this parameter did not exist.