Challenges to magnetic doping of thin films of the Dirac semimetal Cd$_3$As$_2$

Kavli Affiliate: Ke Wang

| First 5 Authors: Run Xiao, Jacob T Held, Jeffrey Rable, Supriya Ghosh, Ke Wang

| Summary:

Magnetic doping of topological quantum materials provides an attractive route
for studying the effects of time-reversal symmetry breaking. Thus motivated, we
explore the introduction of the transition metal Mn into thin films of the
Dirac semimetal Cd3As2 during growth by molecular beam epitaxy. Scanning
transmission electron microscopy measurements show the formation of a Mn-rich
phase at the top surface of Mn-doped Cd3As2 thin films grown using both uniform
doping and delta doping. This suggests that Mn acts as a surfactant during
epitaxial growth of Cd3As2, resulting in phase separation. Magnetometry
measurements of such samples indicate a ferromagnetic phase with out-of-plane
magnetic anisotropy. Electrical magneto-transport measurements of these films
as a function of temperature, magnetic field, and chemical potential reveal a
lower carrier density and higher electron mobility compared to pristine Cd3As2
films grown under similar conditions. This suggests that the surfactant effect
might also serve to getter impurities. We observe robust quantum transport
(Shubnikov-de Haas oscillations and an incipient integer quantum Hall effect)
in very thin (7 nm) Cd3As2 films despite being in direct contact with a
structurally disordered surface ferromagnetic overlayer.

| Search Query: ArXiv Query: search_query=au:”Ke Wang”&id_list=&start=0&max_results=10

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