Niggas, A., Hao, M., Richter, P., Simperl, F., Blödorn, F., Cap, M., Kero, J., Hofmann, D., Bellissimo, A., Burgdörfer, J., Seyller, T., Wilhelm, R. A., Libisch, F., & Werner, W. S. M. (2025). Identifying electronic doorway states in secondary electron emission from layered materials. Physical Review Letters, 135(16), Article 166401. https://doi.org/10.1103/qls7-tr4v

Werl, M., Koller, T., Haidegger, P., Wrathall, S., Eßletzbichler, L., Niggas, A., Aumayr, F., Tökési, K., & Wilhelm, R. A. (2025). Lifetime of a freely decaying hollow atom. Physical Review Research (PRResearch), 7(1), Article 013176. https://doi.org/10.1103/PhysRevResearch.7.013176

Niggas, A., Aumayr, F., & Wilhelm, R. A. (2025). Trajectory-dependent highly charged ion-induced electron yield from single-layer graphene. Physica Scripta, 100(1), 1–7. https://doi.org/10.1088/1402-4896/ad94af

Thima, D., Niggas, A., Werl, M., Szabo, G., Laux, P., Schmidt, M., Zschornack, G., Aumayr, F., & Wilhelm, R. A. (2024). A compact electron beam ion source for highly charged ion experiments at large-scale user facilities. Journal of Physics B: Atomic, Molecular and Optical Physics, 57(16), 1–7. https://doi.org/10.1088/1361-6455/ad6384

Niggas, A., Werl, M., Aumayr, F., & Wilhelm, R. A. (2024). Charge exchange of slow highly charged ions from an electron beam ion trap with surfaces and 2D materials. Journal of Physics B: Atomic, Molecular and Optical Physics, 57, Article 072001. https://doi.org/10.1088/1361-6455/ad2e2a

Chirita-Mihaila, M. C., Szabo, G., Redl, A., Goldberger, M., Niggas, A., & Wilhelm, R. A. (2024). Generation of ultrashort ion pulses from ultrafast electron-stimulated desorption. Physical Review Research (PRResearch), 6(3), L0320661–L0320668. https://doi.org/10.1103/PhysRevResearch.6.L032066

Niggas, A., Fischer, L., Kretschmer, S., Werl, M., Biber, H., Speckmann, C., McEvoy, N., Kotakoski, J., Aumayr, F., Krasheninnikov, A. V., & Wilhelm, R. A. (2023). Charge-exchange-dependent energy loss of H and He in freestanding monolayers of graphene and MoS₂. Physical Review A, 108(6), 0628231–0628238. https://doi.org/10.1103/PhysRevA.108.062823

Szabo, G., Jany, B. R., Muckenhuber, H., Niggas, A., Lehner, M., Janas, A., Szabo, P., Gan, Z., George, A., Turchanin, A., Krok, F., & Wilhelm, R. A. (2023). Charge-State-Enhanced Ion Sputtering of Metallic Gold Nanoislands. Small, Article 2207263. https://doi.org/10.1002/smll.202207263

Grossek, A. S., Niggas, A., Wilhelm, R. A., Aumayr, F., & Lemell, C. (2022). Model for Nanopore Formation in Two-Dimensional Materials by Impact of Highly Charged Ions. Nano Letters, 22(23), 9679–9684. https://doi.org/10.1021/acs.nanolett.2c03894

Niggas, A., Schwestka, J., Balzer, K., Weichselbaum, D., Schlünzen, N., Heller, R., Creutzburg, S., Inani, H., Tripathi, M., Speckmann, C., McEvoy, N., Susi, T., Kotakoski, J., Gan, Z., George, A., Turchanin, A., Bonitz, M., Aumayr, F., & Wilhelm, R. A. (2022). Ion-Induced Surface Charge Dynamics in Freestanding Monolayers of Graphene and MoS2 Probed by the Emission of Electrons. Physical Review Letters, 129(8), 086802-1-086802–086809. https://doi.org/10.1103/PhysRevLett.129.086802

Creutzburg, S., Mergl, M., Hübner, R., Jirka, I., Erb, D., Heller, R., Niggas, A., Grande, P. L., Aumayr, F., Wilhelm, R. A., Kalbac, M., & Facsko, S. (2021). Fluorination of graphene leads to susceptibility for nanopore formation by highly charged ion impact. Physical Review Materials, 5(074007). https://doi.org/10.1103/physrevmaterials.5.074007

Creutzburg, S., Niggas, A., Weichselbaum, D., Grande, P. L., Aumayr, F., & Wilhelm, R. A. (2021). Angle-dependent charge exchange and energy loss of slow highly charged ions in freestanding graphene. Physical Review A, 104(042806). https://doi.org/10.1103/physreva.104.042806

Niggas, A., Creutzburg, S., Schwestka, J., Wöckinger, B., Gupta, T., Grande, P. L., Eder, D., Marques, J. P., Bayer, B. C., Aumayr, F., Bennett, R., & Wilhelm, R. A. (2021). Peeling graphite layer by layer reveals the charge exchange dynamics of ions inside a solid. Communications Physics, 4(180). https://doi.org/10.1038/s42005-021-00686-1

Creutzburg, S., Schwestka, J., Niggas, A., Inani, H., Tripathi, M., George, A., Heller, R., Kozubek, R., Madauß, L., McEvoy, N., Facsko, S., Kotakoski, J., Schleberger, M., Turchanin, A., Grande, P. L., Aumayr, F., & Wilhelm, R. A. (2020). Vanishing influence of the band gap on charge exchange of slow highly charged ions in freestanding-single layer MoS₂. Physical Review B, 102(4), Article 045408. https://doi.org/10.1103/physrevb.102.045408

Lohmann, S., Niggas, A., Charnay, V., Holeňák, R., & Primetzhofer, D. (2020). Assessing electron emission induced by pulsed ion beams: A time-of-flight approach. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 479, 217–221. https://doi.org/10.1016/j.nimb.2020.06.026

Niggas, A., Schwestka, J., Creutzburg, S., Gupta, T., Eder, D., Bayer, B. C., Aumayr, F., & Wilhelm, R. A. (2020). The role of contaminations in ion beam spectroscopy with freestanding 2D materials: a study on thermal treatment. The Journal of Chemical Physics, 153(1), 014702. https://doi.org/10.1063/5.0011255

Schwestka, J., Inani, H., Tripathi, M., Niggas, A., McEvoy, N., Libisch, F., Aumayr, F., Kotakoski, J., & Wilhelm, R. A. (2020). Atomic-Scale Carving of Nanopores into a van der Waals Heterostructure with Slow Highly Charged Ions. ACS Nano, 14(8), 10536–10543. https://doi.org/10.1021/acsnano.0c04476

Szabo, P. S., Biber, H., Jäggi, N., Brenner, M., Weichselbaum, D., Niggas, A., Stadlmayr, R., Primetzhofer, D., Nenning, A., Mutzke, A., Sauer, M., Fleig, J., Foelske-Schmitz, A., Mezger, K., Lammer, H., Galli, A., Wurz, P., & Aumayr, F. (2020). Dynamic potential sputtering of lunar analog material by solar wind ions. Astrophysical Journal, 891(1), 100. https://doi.org/10.3847/1538-4357/ab7008

Schwestka, J., Niggas, A., Creutzburg, S., Kozubek, R., Heller, R., Schleberger, M., Wilhelm, R. A., & Aumayr, F. (2019). Charge-exchange-driven low-energy electron splash induced by heavy ion impact on condensed matter. Journal of Physical Chemistry Letters, 10(17), 4805–4811. https://doi.org/10.1021/acs.jpclett.9b01774

Schwestka, J., Melinc, D., Heller, R., Niggas, A., Leonhartsberger, L., Winter, H., Facsko, S., Aumayr, F., & Wilhelm, R. A. (2018). A versatile ion beam spectrometer for studies of ion interaction with 2D materials. Review of Scientific Instruments, 89(8), 085101. https://doi.org/10.1063/1.5037798