Highly interface-dependent spin transport in an Fe-Mn(DBTAA)-Fe single molecule spintronic device

Understanding the spinterface between magnetic electrodes and molecules, and realizing the controllable spin filtering effect, are crucial for the development of high-performance molecular devices, but both still face big challenges. Here, based on first-principles calculations of an Fe-Mn(DBTAA)-Fe single molecule spintronic device, we unveil that spin filtering efficiency is highly dependent on interface configurations, which can modulate and even reverse the spin polarization of tunnelling electrons. For Fe-Mn(DBTAA)-Fe, a varied spin filtering from -93% to +75% is observed. The underlying mechanism could be attributed to the distinct magnetic and electronic couplings between the Fe electrode and the Mn(DBTAA) molecule in different interface configurations. This work not only highlights the importance of a magnetic electrode-molecule interface, but also implies that through suitable interface design, the performance, e.g., of the spin filtering channel of single molecule spintronic devices, can be flexibly tuned.

Spin-Seebeck effect and thermal colossal magnetoresistance in the narrowest zigzag graphene nanoribbons

Device miniaturization and low-energy dissipation are two urgent requirements in future spintronics devices. The narrowest zigzag graphene nanoribbons (ZGNRs), which are composed of just two coupled carbon-atom chains connected with carbon tetragons, are promising candidates that meet both of the above requirements well. Using the first-principles calculations combined with non-equilibrium Green's function approach, thermal spin-dependent transport through this kind of narrow ZGNR is investigated, and several exotic thermal spin-resolved transport properties are uncovered: (i) when an external magnetic field is applied, the ZGNRs are transited from the intrinsic semiconducting to the metallic state, and the thermal colossal magnetoresistance effect occurs with order of magnitudes up to 10⁴ at room temperature; (ii) the thermal spin-dependent currents display a thermal negative differential resistance effect, and a well-defined spin-Seebeck effect (SSE) together with a pure thermal spin current occurs; and (iii) under suitable device temperature settings, a nearly perfect spin-filtering effect occurs in these narrowest ZGNRs. The theoretical results not only uncover the narrowest nanoribbon structures to realize the SSE and other inspiring thermal spin transport features, but also push carbon-based material candidates towards thermoelectric conversion device applications.

Spin-polarized and thermospin-polarized transport properties of phthalocyanine dimer based molecular junction with different transition metal atoms

Based on the first-principles density functional theory combined with the non-equilibrium Green's function method, we have studied the spin-polarized and thermospin-polarized transport properties of phthalocyanine (Pc) dimer based molecular junction with different transition metal (TM = Mn, Fe, Co, Ni) atoms. Our results show that the spin-polarized and thermospin-polarized transport properties can be effectively tuned by changing the central TM atoms, and only the MnPc dimer system exhibits perfect spin/thermal-spin filtering and sizeable giant magnetoresistance (GMR)/thermal-GMR effects. Meantime, the MnPc dimer system reveals a low-bias negative differential resistance effect under the parallel magnetic configuration. These findings suggest that the MnPc dimer system has great potential in developing the high-performance multifunctional spintronic and spin caloritronic devices.

Pure spin current and phonon thermoelectric transport in a triangulene-based molecular junction

A triangulene-based molecular junction: a favorable spintronic device with pure spin current and efficient phonon thermoelectric transport.

Spin-polarized transport properties in some transition metal dithiolene complexes

Spin filtering materials are of great current interest in part due to their applications in molecular electronics. In this study, we carried out a theoretical investigation on the charge transport properties of transition metal (TM) dithiolene complexes with TM = Ni, Fe and Mn by using non-equilibrium Green's function/density functional theory (NEGF-DFT) methods. The characteristics of current-voltage and spin-resolved transmission spectra pointed out that Ni complexes are non-polarized, while Fe and Mn complexes exhibit high polarization and can be regarded as excellent candidates for spin-filtering materials with high spin-filtering efficiency. These differences were rationalized on the basis of electron delocalization over the molecular junction of the partial distribution of α- and β-spin molecular projected self-consistent Hamiltonian (MPSH) orbitals, and also the first eigenchannels of molecular junctions.

A theoretical study on charge transport of dithiolene nickel complexes

The effect of chemical structures on the charge transport characteristics of dithiophene nickel complexes was studied using DFT and NEGF-DFT methods.

Theoretical study of electron tunneling through the spiral molecule junctions along spiral paths

A theoretical study of electron transport in spiral-shaped molecules along spiral paths is executed by the first principles calculations.