Postdoctoral Researcher Advanced Modeling Techniques for Ab-Initio Transport of Next-Generation 2D Devices
What you will do
The discovery of graphene in 2004 has sparked a renewed interest for materials in 2-D form. Among other materials, transition metal dichalcogenides (TMDs) or black phosphorus (BP) are widely investigated by the scientific community in mono- or a few-layer form using for instance a Van-der-Waals homo- or heterojunction layer stack. Other important classes of low-dimensional materials are nanowires or nanotubes made of Si but also Ge, III-V, Carbon or more exotic materials. Some low-dimensional materials may also feature intriguing new quantum states of matter, like the appearance of topologically protected states in topological-insulator (TI) materials.
Atomistic full-band quantum transport simulations including electron-phonon scattering have been shown indispensable to consider intricate band-structure and transport effects, as for example narrow valleys and the need for phonon mediated transport in a MoS2 transistor and accurately assess the performance of these devices. In addition, as there are many low-dimensional materials to explore on which not much is known, a parameter-free or Ab-Initio atomistic method, such as Density-Functional-Theory (DFT), is best. A state-of-the art simulator for 2-D and other low-dimensional material-based devices uses a dissipative localized-orbital-basis Ab-Initio atomistic Non-Equilibrium Green’s Functions (NEGF) algorithm. We have built such a simulator. The device Hamiltonian is created in our simulator using as building blocks DFT supercell elements of the materials or combination of materials of interest (e.g., computed by VASP or QUANTUM EXPRESSO and transformed in a localized orbital-basis, as needed for transport, using the maximally-localized Wannier-function method). We also have the possibility to improve the simulation speed by several orders of magnitude, using atomistic acceleration (mode-space NEGF) techniques that we have pioneered.
The proposed work relies on the development of advanced modeling approaches to go beyond, and assess the impact of some of the traditional approximations that are typically used, even in atomistic quantum transport simulations. Among other approximations, the usage of deformation potentials and bulk equilibrium phonons, or the usage of a bulk material dielectric constant rather than explicitly accounting for the core-electron and ion screening pose question in low-dimensional materials where the granularity of matter cannot be neglected (e.g., what is the meaning of the dielectric constant in a Van-der-Waals gap?). The proposed work will envision fully coupled atomistic electron and phonon transport models (phonon transport will also allow for computing heat transport for instance), or will explicitly include the core-electron and, if needed, the ion screening to remove the need of using a material related dielectric constant in the simulations. The developed advanced models will then be applied to explore the physics and performances of innovative low dimensional material (2D, TI...) devices for future CMOS or quantum computing applications.
What we do for you
We offer you the opportunity to join one of the world’s premier research centers in nanotechnology at its headquarters in Leuven, Belgium. With your talent, passion and expertise, you’ll become part of a team that makes the impossible possible. Together, we shape the technology that will determine the society of tomorrow.
We are proud of our open, multicultural, and informal working environment with ample possibilities to take initiative and show responsibility. We commit to supporting and guiding you in this process; not only with words but also with tangible actions. Through imec.academy, 'our corporate university', we actively invest in your development to further your technical and personal growth.
We are aware that your valuable contribution makes imec a top player in its field. Your energy and commitment are therefore appreciated by means of a competitive salary.
Who you are
- You have a PhD in the field of Physics, Electrical Engineering or equivalent.
- You have experience in Quantum transport and Physics.
- Specific experience in NEGF is a strong plus.
- We value experience with programming and high-performance computing (e.g., C++ and MPI).
- You have at the very least some basic knowledge about nanoelectronics and device physics.
- You are a constructive team player and actively share experience and knowledge with colleagues.
- Your creativity, persistence and passion for what you do are highly valued.
- We are looking for your excellent networking and communication skills in English, as you will work in a multicultural team and closely with our partners.
This postdoctoral position is funded by imec through KU Leuven. Because of the specific financing statute which targets international mobility for postdocs, only candidates who did not stay or work/study in Belgium for more than 24 months in the past 3 years can be considered for the position (short stays such as holiday, participation in conferences, etc. are not taken into account).