Excited state dynamics in a sodium and iodine co-doped lead telluride nanowire

ABSTRACT

Materials that convert wasted heat into electricity are needed to help solve global warming and other climate challenges. Thermoelectric nanowires are novel metamaterials for such applications. Non-adiabatic coupling computations are critical in understanding thermally activated charge transfer in thermoelectric materials. Here, non-adiabatic computations are used to evaluate electron relaxation rates in lead telluride nanowires. This work reports results on PbTe (lead telluride) atomistic models doped with sodium and iodine that contain 288 atoms in simulation cells with periodic boundary conditions. The calculations are performed on the basis of ground-state DFT under the VASP software. The transitions between states are modelled in terms of Redfield equation of motion parameterised by on-the-fly non-adiabatic couplings along thermalised molecular dynamic trajectory. The initial states are approximated by the promotion of an electron from occupied to unoccupied Kohn–Sham orbital. In each transition, the change of the energy and spatial charge distribution with respect to time were calculated, demonstrating formation of charge transfer. The trends of electron and hole relaxation rates comply with the energy gap law.

GRAPHICAL ABSTRACT

KEYWORDS:

• Lead telluride
• density matrix
• charge transfer
• co-doping
• non-adiabatic

Acknowledgement

The authors thank DOE BES NERSC facility for computational resources, allocation award #91202, ‘Computational Modeling of Photo-catalysis and Photo-induced Charge Transfer Dynamics on Surfaces’ supported by the Office of Science of the DOE under contract no. DE-AC02-05CH11231. DSK acknowledges support of the National Science Foundation under grant numbers CHE-2004197 and CHE-1944921. The work of T.M.I. was performed under the state assignment of IGM SB RAS. KG acknowledges support of the Department of Physics, NDSU and the American Physical Society Bridge Program. The authors thank David Micha and Svetlana Kilina for inspiring ideas. They also thank Yulun Han, Fatima, Aaron Forde for discussions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors thank DOE BES NERSC facility for computational resources, allocation award #91202, ‘Computational Modeling of Photo-catalysis and Photo-induced Charge Transfer Dynamics on Surfaces’ supported by the Office of Science of the DOE under contract no. DE-AC02-05CH11231. DK acknowledges support of the National Science Foundation under grant number CHE-2004197. KG acknowledges support of the Department of Physics, NDSU and the American Physical Society Bridge programme; Division of Chemistry; National Science Foundation [grant number 1944921].