Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 35: Poster I
HL 35.14: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
Topological phases in interfacial phase-change materials — •Peter Schmitz1,3, Wei Zhang2, Yuriy Mokrousov3, and Riccardo Mazzarello1 — 1Institute for Theoretical Solid State Physics, RWTH Aachen — 2CAMP Nano, Xi’an Jiaotong university, China — 3IAS-1 and JARA, Forschungszentrum Jülich
We investigate the topological, spectral and structural properties of [Sb2Te3]x[GeTe]y compounds, some of which are interfacial phase-change materials (IPCMs), as a function of strain and stacking sequence using density functional theory.
Induced by electric fields and heat, IPCMs can perform fast reversible transitions between crystalline states of different stacking. Since they possess strong SOC and a TI+NI layering, they are a promising platform for nontrivial interface states and switching between topological phases. So far they were shown to exhibit TIs and unstable TI/NI transition points [1], yet no consistent classification exists.
We analyze if the novel 3D topological Dirac semimetal (TDSM) phase [2] is relevant to these C3 systems: Under parameter variation, 2 cones move through the bulk spectrum, gapped due to symmetry breaking potentials between the blocks which enables nonzero 3D Z2 invariants. We show that corresponding states are localized at the interfaces of iPCMs and the effective topological phase is controlled by their van der Waals interaction.
[1] J. Tominaga et al, Adv. Mat. Inter. 1 (2014)
[2] B. Yang and N. Nagaosa, Nature Commun. 5, 4898 (2014)