Topologically-imposed vacancies and mobile solid 3He on carbon nanotube

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Nature Communications, Volume 13, issue 1
Low dimensional fermionic quantum systems are exceptionally interesting because they reveal distinctive physical phenomena, including among others, topologically protected excitations, edge states, frustration, and fractionalization. Our aim was to confine 3He on a suspended carbon nanotube to form 2-dimensional Fermi-system. Here we report our measurements of the mechanical resonance of the nanotube with adsorbed sub-monolayer down to 10 mK. At intermediate coverages we have observed the famous 1/3 commensurate solid. However, at larger monolayer densities we have observed a quantum phase transition from 1/3 solid to an unknown, soft, and mobile solid phase. We interpret this mobile solid phase as a bosonic commensurate crystal consisting of helium dimers with topologically-induced zero-point vacancies which are delocalized at low temperatures. We thus demonstrate that 3He on a nanotube merges both fermionic and bosonic phenomena, with a quantum phase transition between fermionic solid 1/3 phase and the observed bosonic dimer solid.
Funding Information: We are grateful to Henri Godfrin, Ari Harju, Ville Havu, Andreas Huettel, Martti Puska, and Erkki Thuneberg for discussions, and Petri Tonteri from Densiq Ltd. (90620 Oulu, Finland) for providing us with the ultra-pure grafoil. We thank Miika Haataja for measuring the surface area of the grafoil sample and Qiang Zhang for participation in the optimization of the CNT process. Funding: This work was supported by Academy of Finland projects No. 314448 (BOLOSE), No. 312295 (CoE, Quantum Technology Finland), and No. 316572 (CNTstress). The research leading to these results has received funding from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement No 824109 (EMP), under ERC Grant No. 670743 (QuDeT), and in part by Marie-Curie training network project (OMT, No. 722923). J.-P.K. is grateful for the financial support from Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters. This research project utilized the Aalto University OtaNano/LTL infrastructure. | openaire: EC/H2020/670743/EU//QuDeT | openaire: EC/H2020/824109/EU//EMP | openaire: EC/H2020/722923/EU//OMT
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Todoshchenko, I, Kamada, M, Kaikkonen, J P, Liao, Y, Savin, A, Will, M, Sergeicheva, E, Abhilash, T S, Kauppinen, E & Hakonen, P J 2022, ' Topologically-imposed vacancies and mobile solid 3 He on carbon nanotube ', Nature Communications, vol. 13, no. 1, 5873, pp. 1-9 .