Antonija Grubisic-Cabo1
University of Groningen1
The fundamental physics of solids, including two-dimensional (2D) materials, is inherently linked to their electronic band structure. The investigation of the electronic band structure is therefore of paramount significance for understanding, tailoring and discovering new states of matter. In the case of 2D materials, such as graphene and single layer transition metal dichalcogenides, control of the electronic structure can be achieved by altering their surroundings, as the electronic structure of 2D materials is highly sensitive to the surrounding environment. However, robust methods for the determination of the electronic structure are required to ascertain the effects of those alterations. In this talk, I will present time- and angle-resolved photoemission spectroscopy (TR-ARPES) as a technique for the electronic structure studies on the ultrafast, femtosecond scale [1], and as means to achieve control over 2D materials by light [2].<br/>Furthermore, I will introduce an innovative preparation method for 2D materials, kinetic <i>in situ</i> single-layer (KISS) method [3]. Using KISS method, exfoliation of 2D materials can be performed directly in ultra-high vacuum, and large flakes of excellent crystallinity and purity can be obtained. Multiple semiconducting and metallic transition metal dichalcogenides were exfoliated onto Au, Ag and Ge substrates, showing the versatility of the technique, and characterised by ARPES. Importantly, the proposed method is straightforward, simple, and does not require any specialised equipment. This technique is ideally suited for the electronic structure research of air-sensitive 2D materials since the sample preparation process happens entirely in ultra-high vacuum.<br/><br/>References:<br/><b><u>1.</u></b> Majchrzak, P., Volckaert, K., <b>Grubisic-Cabo, A.</b>, Biswas, D., Bianchi, M., Mahatha, S. K., Dendzik, M., Andreatta, F., Grønborg, S. G., Markovic, I., Riley, J. M .,Johannsen, J. C.,Lizzit, D., Bignardi, L., Lizzit, S., Cacho, C., lexander, O., Matselyukh, D., Wyatt, A., Chapman, R. T., Springate, E., Grioni, M., Lauritsen, J. V., King, P. D. C., Sanders, C. E., Miwa, J. A., Hofmann, P. & Ulstrup, S., <i>”Spectroscopic view of ultrafast charge carrier dynamics in single- and bilayer transition metal dichalcogenide semiconductors”</i>, Journal of Electron Spectroscopy and Related Phenomena 250, 147093 (2021)<br/><u><b>2.</b></u> Beyer, H., Rohde, G., <b>Grubisic-Cabo, A.</b>, Stange, A., Jacobsen, T., Bignardi, L., Lizzit, D., Lacovig, P., Sanders, C.E., Lizzit, S., Rossnagel, K., Hofmann, P. & Bauer, M., <i>”80% valley polarization of free carriers in singly oriented single-layer WS<sub>2</sub> on Au(111)”</i>, Physical Review Letters 123, 236802 (2019)<br/><u><b>3.</b></u> <b>Grubisic-Cabo, A.</b>, Michiardi, M., Sanders, C.E., Bianchi, M., Curcio, D., Phuyal, D., Guo, Q. & Dendzik, M., <i>"In situ exfoliation method of large-area 2D materials”</i>, Advanced Science 2301243 (2023)