Conetronics in 2D Metal-Organic Frameworks: Double Dirac Cones, Magnetic Half Dirac Cones and Quantum Anomalous Hall Effect

TL;DR

This paper predicts novel electronic properties in 2D metal-organic frameworks, including double Dirac cones, spin-polarized Dirac points, and potential quantum anomalous Hall effects, enabling advanced spintronic and conetronic devices.

Contribution

It introduces theoretical predictions of switchable double Dirac cones, spin-polarized conduction channels, and quantum anomalous Hall effects in specific 2D MOFs, expanding their potential for electronic applications.

Findings

Double Dirac cones with different Fermi velocities are switchable by strain.

Spin-polarized Dirac cones are pinned at the Fermi level, enabling spin-selective conduction.

Quantum anomalous Hall effect can occur in MOFs with significant spin-orbit coupling.

Abstract

Based on recently synthesized Ni3C12S12 class 2D metal-organic frameworks, we predict electronic properties of M3C12S12 and M3C12O12, where M is Zn, Cd, Hg, Be, or Mg with no M orbital contributions to bands near Fermi level. For M3C12S12, their band structures exhibit double Dirac cones with different Fermi velocities that are n and p type, respectively, which are switchable by few-percent strain. The crossing of two cones are symmetry-protected to be non-hybridizing, leading to two independent channels in 2D node-line semimetals at the same k-point akin to spin-channels in spintronics, rendering conetronics device possible. The node line rings right at their crossing, which are both electron and hole pockets at the Fermi level, can give rise to magnetoresistance that will not saturate when the magnetic field is infinitely large, due to perfect n-p compensation. For M3C12O12, together with conjugated metal-tricatecholate polymers M3(HHTP)2, the spin-polarized slow Dirac cone center is pinned precisely at the Fermi level, making the systems conducting in only one spin or cone channel. Quantum anomalous Hall effect can arise in MOFs with non-negligible spin-orbit coupling like Cu3C12O12. Compounds of M3C12S12 and M3C12O12 with different M, can be used to build spintronic and cone-selecting heterostructure devices, tunable by strain or electrostatic gating.