Speaker
Description
Topological semimetals are candidate hosts of interesting types of low-energy quasiparticles such as type-I and type-II Dirac and Weyl fermions. A type-III crossing point [1-3] emerges as a theoretical possibility exactly at the border between type-I and II, characterized by a line-like Fermi surface and a flat energy dispersion. We theoretically predict [4] that HfTe2 and ZrTe2 transition metal ditellurides are type-I and type-II Dirac semimetals, respectively. By alloying the two materials, a new HfxZr1-xTe2 alloy with type-III Dirac cone emerges at x=0.2 in combination with 1% in-plane compressive strain [4]. We also provide experimental evidence that by using molecular beam epitaxy, single and few layers of HfTe2 [5], ZrTe2 [6] and Hf0.2Zr0.8Te2 [4] can be grown on InAs(111) substrates, and by using in-situ angle-resolved photoemission spectroscopy, that the Dirac points lie at -or very close to- the Fermi level.
- G. E. Volovik and K. Zhang, J. Low Temp. Phys. 189, 276 (2017).
- H. Liu et al., Phys. Rev. Lett. 120, 237403 (2018).
- L. Jin et al., Phys. Rev. B 101, 045130 (2020).
- S. Fragkos et al., J. Appl. Phys. 129, 075104 (2021).
- S. A. Giamini et al., 2D Mater. 4, 015001 (2017).
- P. Tsipas et al., ACS Nano 12, 1696 (2018).
We acknowledge the financial support from the European Union H2020, Contract No. 824123 - SKYTOP and the Hellenic Foundation for Research and Innovation and the General Secretariat for Research and Technology, under Grant No. 435 (2D-TOP).
| Speaker Country | Greece |
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