Michal Zielinski - Welcome to my webpage.

About me

Welcome and thank you for visiting my webpage.

I am head of Department of Quantum Physics at Institute of Physics, Nicolaus Copernicus University, Torun, Poland.

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Contact information

Office address: Instytut Fizyki UMK, Grudziadzka 5, 87-100; Torun, Poland

Phone: ++48 56 611 2405 (office)

Email: mzielin@fizyka.umk.pl

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Research

atomistic many-body calculation for varius nanosystems include quantum dots, nanowires and nanowire quantum dots, strain effects in semiconductor quantum dots and nanocrystals, 3D interactive computer graphics applications in nanostructure physics
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Sonata project

The project (financed by National Science Centre) focused on theory and computational tools development aiming for atomistic calculations of nanostructure properties under external strain. The improved and newly created software allows for massively-parallel computations for nanosystems with numbers of atoms exceeding 100 million. Results of large scale atomistic calculations have shown a significant effect of external strain on spectral properties of nanowires and nanowire quantum dots. A fundamental role of quantum dot shape symmetry and lattice composition fluctuations [Phys. Rev. B 91, 085303 (2015)]. on excitonic spectra has also been found.
  • Externally strained nanowire quantum dots It has been shown that the lattice mismatched shells allow for a wide range control of excitonic emission energy of InAs/InP nanowire quantum dots [Nano Letters 12, 6202 (2012)] and ZnTe nanowires [Applied Physics Letters 104, 163111 (2014)]. The key factor responsible for the modification of the emission energy is tensile strain due to the nanowire shell. Atomistic theory was successfully applied to estimate the character of combined internal/external strain and the magnitude of excitonic spectra shifts. Atomistic calculations give a clue on how the post-growth process can lead to a nanosystem design of desired specifications. Results of theoretical calculations were in qualitative and quantitative agreement with the experiment, whereas the cited papers were the first in the field. The large degree of control due to strain could be useful for quantum dots and nanowires applications in telecommunication or quantum cryptography.
  • Light-hole excitons in nanowire quantum dots In the project it has also been shown that high aspect ratio (tall) nanowire quantum dots can exhibit light-hole excitonic ground state with a pronounced effect on details of excitonic spectra (excitonic fine structure). Paper Phys. Rev. B 88, 115424 (2013) was the first to discuss properties of light-hole excitons confined in nanowire quantum dots. Nanostructures of such properties could find novel applications in information technology and telecommunication.
  • Dark excitons in low-shape symmetry quantum dots Another important result was obtained for InAs/GaAs self-assembled quantum dots. It has been shown that the low shape symmetry can have a fundamental effect on excitonic spectra and lead to bright and dark excitons mixing [Phys. Rev. B 99, 085403 (2015)]. These results has been recently confirmed by an experiment and could be considered as a stepping stone towards dark excitons manipulation by purely optical means. Dark excitons can effectively form a long-lived, charge neutral qubits with potential applications in quantum information.
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Sonata Bis project

In this project, we intend to formulate theoretical description and perform large-scale calculations of spectral properties of silicon nanodevices doped with single impurity atoms. Single dopant embedded in a host environment of millions of silicon atoms forms a complicated nanosystem where every atoms must be accounted for individually. In other words: every atom matters. Our approach will therefore utilize the atomistic tight-binding method that naturally incorporates effects of quantum confinement, external fields, and atomistic effects such as interfaces steps and composition disorder. We aim to apply our methodology to solve currently untraceable problems where impurity wave-function extends over ten millions of atomic sites. Thanks to close collaboration with the National Institute of Standards and Technology (NIST) we will have the unique ability to correlate the measured and calculated data.

We hire PhDs now!
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