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M. Creutzburg, J. Schwestka, A. Niggas, H. Inani, M. Tripathi, A. George, R. Heller, R. Kozubek, L. Madauß, N. McEvoy, S. Facsko, J. Kotakoski, M. Schleberger, A. Turchanin, P. Grande, F. Aumayr, R. Wilhelm:
"Vanishing influence of the band gap on charge exchange of slow highly charged ions in freestanding single layer MoS₂";
Physical Review B, 102 (2020), 0454081 - 0454088.

Charge exchange and kinetic energy loss of slow highly charged xenon ions transmitted through freestanding
monolayer MoS2 are studied. Two distinct exit charge state distributions, characterized by high and low charge
states, are observed. They are accompanied by smaller and larger kinetic energy losses, as well as scattering
angles, respectively. High charge exchange is attributed to two-center neutralization processes, which take
place in close impact collisions with the target atoms. Experimental findings are compared to graphene as
a target material and simulations based on a time-dependent scattering potential model. Independent of the
target material, experimentally observed charge exchange can be modeled by the same electron capture and
de-excitation rates for MoS2 and graphene. A common dependence of the kinetic energy loss on the charge
exchange for MoS2 as well as graphene is also observed. Considering the similarities of the zero band-gap
material graphene and the 1.9 eV band-gap materialMoS2, we suggest that electron transport on the femtosecond
timescale is dominated by the strong influence of the ion´s Coulomb potential in contrast to the dispersion defined
by the material´s band structure.

http://dx.doi.org/10.1103/PhysRevB.102.045408

https://doi.org/10.1103/PhysRevB.102.045408