@misc{SulaimanBussSanchezBarquillaetal., author = {Sulaiman, Cathy and Buß, Lars and S{\´a}nchez-Barquilla, Raquel and Falta, Jens and Flege, Jan Ingo}, title = {In-situ growth and characterization of 2D TaSe2 on Au(111)}, series = {Verhandlungen der DPG, Regensburg 2025}, journal = {Verhandlungen der DPG, Regensburg 2025}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Group V dichalcogenides such as TaX2 (X = S, Se, T) have extensively been investigated in recent decades due to their diverse electron correlation effects, including the occurrence of charge density waves and Mott-Hubbard transitions. In 2D, two polytypes, 1T and 1H, exist, which exhibit distinct properties, making selective growth of each polytype crucial. Using low-energy electron microscopy (LEEM), we have successfully observed the growth of two TaSe2 phases on Au(111) in situ after the co-deposition of Ta and Se. At elevated temperature, micron-sized, triangle-shaped islands with bright contrast nucleate first and grow at a higher rate. However, this phase turns out to be meta-stable as it suddenly transitions into a more stable phase (with dark contrast) and continues to grow at a reduced rate. Low-energy electron diffraction shows the presence of TaSe2; bandstructure-sensitive I(V)-LEEM analysis reveals substantial differences in electron reflectivity between both phases. A comparison with TaS2 suggests that the metastable and stable phases are 1T- and 1H-TaSe2, respectively.}, language = {en} } @misc{BussSulaimanSanchezBarquillaetal., author = {Buß, Lars and Sulaiman, Cathy and S{\´a}nchez-Barquilla, Raquel and Cojocariu, Iulia and Szpytma, Marcin and Mente{\c{s}}, Tevfik Onur and Locatelli, Andrea and Falta, Jens and Flege, Jan Ingo}, title = {Rise and fall of 1T-TaS₂ : epitaxial growth of monolayer TaS₂ on Au(111)}, series = {Physical review materials}, volume = {9}, journal = {Physical review materials}, number = {7}, publisher = {American Physical Society (APS)}, address = {College Park, MD}, issn = {2475-9953}, doi = {10.1103/1bxg-yvw2}, pages = {1 -- 9}, abstract = {Monolayer tantalum disulfide epitaxially grown on Au(111) is studied in real time during molecular beam epitaxy using low-energy electron microscopy and microdiffraction. Complementary x-ray photoelectron emission microscopy provides insight into the chemical and electronic structure of the grown layers. Our study reveals a previously unreported growth mechanism where the formation of 2⁢H-TaS2 proceeds via a transient 1⁢T-TaS2 phase. The 1⁢T-TaS2 phase exhibits a significantly higher growth rate than the 2⁢H-TaS2 phase, with growth proceeding mainly in the 1T phase. By comparison with TaSe2 on Au(111), we find that this growth mechanism is common to other Ta-based transition-metal dichalcogenides on Au(111). Furthermore, we find spectroscopic evidence for the presence of charge-density-wave order in 1⁢T-TaS2 on Au(111). These findings provide perspectives on the growth dynamics and phase control of TaS2, opening up avenues for tailoring its electronic properties through substrate interaction and phase engineering.}, language = {en} }