| Abstract: | Designer quantum materials that realize electronic responses not found
in naturally occurring materials have recently attracted intense
interest. In particular, using van der Waals (vdW) heterostructures,
it is possible to realize the desired physics through the engineered
interactions between the different components. Achieving designer
quantum states in vdW heterostructures would facilitate their
incorporation into future device structures and potentially allow
further control through e.g. electrostatic gating.
In my talk, I will outline our recent results on realizing topological
superconductivity and artificial heavy fermion systems in vdW
heterostructures [1-3]. The samples are grown via molecular-beam
epitaxy (MBE) in ultra-high vacuum and studied using low-temperature
scanning tunneling microscopy (STM). Topological superconductivity can
be realized by combining ferromagnetic CrBr3 on a superconducting
NbSe2 substrate [1,2]. This brings together out of plane
ferromagnetism with Rashba spin-orbit interactions and s-wave
superconductivity, which are the necessary ingredients for topological
superconductivity. On the other hand, artficial heavy fermion systems
can be realized by coupling localized magnetic moments with mobile
conduction electrons. We achieve this experimentally by bringing
together 1T-TaS2, where a strong charge-density wave modulation
results in a formation of localized electronic states, and normal
metal layer 1H-TaS2 [4]. These examples highlight the versatility of
vdW heterostructures in realizing quantum states that are difficult to
find and to control in naturally occurring materials.
References
[1] S. Kezilebieke, M. N. Huda, V. Vaňo, M. Aapro, S. C. Ganguli, O.
J. Silveira, S. Głodzik, A. S. Foster, T. Ojanen, P. Liljeroth,
Topological superconductivity in a designer van der Waals
heterostructure, Nature 588, 424 (2020).
[2] S. Kezilebieke, V. Vaňo, M.N. Huda, M. Aapro, S.C. Ganguli, P.
Liljeroth, J.L. Lado, Moiré-enabled topological superconductivity,
arxiv:2011.09760.
[3] V. Vaňo, M. Amini, S.C. Ganguli, G. Chen, J.L. Lado, S.
Kezilebieke, P. Liljeroth, Artificial heavy fermions in a van der
Waals heterostructure, arxiv:2103.11989. |