QTCAD® version 1.5 is available!

We are excited to release a new update to QTCAD^®, which includes major dramatic improvements to key solvers and this should please very much our users.

As shown below, we focused mainly on performance in this release for a better usage of QTCAD^® in its essence dedicated to increasing the potential for R&D and design works.

Main updates and new features in this version 1.5.0 are the following:

• Accelerated Coulomb integrals using a filtering method that enables dropping
  terms that contribute negligibly to the many-body Hamiltonian.
  Until memory becomes saturated, this approach can achieve a complexity scaling
  of Coulomb integrals with respect to the number of single-particle basis states
  N of order N^2, a major improvement over the N^4 scaling of brute-force
  methods.
• Improved multithreading in the single-particle Schrödinger solver, for both
  electrons and holes. This can lead to important speedups for calculations on
  meshes with more than 10,000 nodes.
• New tutorial presenting an improved charge stability diagram calculation
  workflow that combines the non-equilibrium Green’s (NEGF) function and
  master-equation approaches to compute current flowing through a quantum dot
  in the Coulomb blockade regime. This new approach enables users to obtain an
  absolute value for the current while relaxing several assumptions required to
  apply the WKB method that was previously used for the same purpose.
• Improved multithreading and acceleration of the multi-valley effective mass
  theory (MVEMT) solver, whose constructor was also standardized by moving
  several keyword arguments into an input SolverParams object.
• Generalized the MVEMT solver to support 1D simulations in addition to the
  already available 3D case.
• Modernized and extended the MVEMT tutorials to include:
  • A 1D calculation of valley splitting as a function of electric field
    at an interface between silicon and silicon dioxide.
  • A 3D calculation and analysis of a phosphorus donor in silicon including
    a central cell correction.
• Added the possibility to define a custom charge-density profile in the
  point-charge feature. An example for usage of this feature is now provided
  in the point-charge tutorial, in which the influence of a single ionized
  phosphorus donor on the orbital energy levels of a quantum dot is studied.
• Added an “”Exponential”“ distribution to the pre-defined point-charge
  density distributions along with “”Gaussian”“ and “”Uniform”“.
• Support for the Gmsh HXT meshing algorithm within the linear and non-linear
  Poisson adaptive-mesh solvers. HXT meshing can often be faster than the
  default Delaunay meshing algorithm.
• Extended the features within the “analysis“ module:
  • New “plot_slice“ function to plot a 3D function defined at mesh nodes
    over an arbitrary 2D slice using PyPlot. This function complements the
    already-existing “plot_slices“ (plural) function which plots orthogonal
    slices in 3D.
  • New “region_statistics“ function to compute statistics of a 3D function
    over a region.
  • New “point_eval“ function to evaluate a 3D function defined at mesh nodes
    at a single arbitrary point in space through finite-element interpolation.
  • The “analyze_dot“ function now supports the calculation of excited-state
• Added scripts for the convergence analysis presented in the tutorial
  on exchange in an FD-SOI double quantum dot.
• Tables describing default available materials and their properties are now
  available in the online documentation.

Once again, we thank all our active users and partners both from Academic and Industrial organizations very much for their trust!

To join the QTCAD® community, simply create your user account on our portal and download the tool to test it: https://portal.nanoacademic.com/ T

he online documentation has been updated, you will find all the information on this new version here: QTCAD 1.5 — QTCAD 1.5 documentation (nanoacademic.com).

Link to the latest QTCAD brochure: CLICK HERE

We will be present at the Q2B 2024 Silicon Valley tradeshow and conference in Santa Clara, CA on Dec. 10 and 11: let’s meet there!More exciting news will follow soon for our subscribers closely following the development of QTCAD^®.

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Thank you very much for your interest and continued support.

Nanoacademic’s Quantum Technology team in charge of QTCAD^®.