Weyl node assisted conductivity switch in interfacial phase change memory with van der Waals interfaces

Abstract

The interfacial phase-change memory (iPCM) GeTe/Sb2Te3, promising candidates for the next generation non-volatile random-access memories, exhibits fascinating topological properties. Depending on the atomic-layer-stacking sequence of the GeTe block, the iPCM can be either in the SET (Ge-Te-Ge-Te) or RESET (Te-Ge-Ge-Te) states, where the former exhibits ferroelectric polarization and electrical conductivity two orders of magnitude larger than that of the RESET state. But, its origin remains elusive. Here, we predict the emergence of a Weyl semimetal phase in the SET state induced by the ferroelectric polarization which breaks the crystal inversion symmetry. We show that the giant conductivity enhancement of the SET phase is due to the appearance of gapless Weyl nodes. The Ge-Te- or Sb-Te-terminated surfaces of Weyl semimetal iPCM produce surface states with completely distinctive topology, where the former consists solely of Fermi arcs while the latter consists of both closed Fermi surface and open Fermi arcs. The iPCM with van der Waals interfaces offers an ideal platform for exploiting the exotic Weyl properties for future memory device applications.

9 pages, 5 figures

References in corpus (6)

• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Weyl semimetals from noncentrosymmetric topological insulators
• Ferroelectricity and Rashba effect in GeTe
• Universal phase diagrams for the quantum spin Hall systems
• Topological insulating behaviour in conducting property of crystalline Ge-Sb-Te
• Pressure effects on crystal and electronic structure of bismuth tellurohalides

Cited by in corpus (5)

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• Photon Energy Dependence of Kerr Rotation in Chalcogenide Superlattices
• All-optical detection of periodic structure of chalcogenide superlattice using coherent folded acoustic phonons