Prediction of crossing nodal-lines and large intrinsic spin Hall conductivity in topological Dirac semimetal Ta3As family

Abstract

Topological insulators (TIs) are considered as ideal platforms for generating large spin Hall conductivity (SHC), however, the bulk carrier problem, which is unavoidable in TIs, hinders their practical applications. Recently, topological semimetals (TSMs) have been proposed to achieve large SHC to replace TIs. However, the ideal TSM candidates with large SHC are still lacking. In terms of first-principles calculations, we predict that Ta3As family compounds exhibit complex crossing nodal-lines (CNL) properties in absence of the spin-orbit coupling (SOC). However, they transfer to Dirac TSMs under the influence of strong SOC, and present large SHC around Fermi level in particular. Remarkably, the SHC value of Ta3Y (Y = As, Sb, Bi) is around 1500–1700 $$(\hbar /e)({\mathrm{{\Omega}}} \cdot {\mathrm{cm}})^{ - 1}$$ ( ħ / e ) ( Ω ⋅ cm ) − 1 , which is comparable to noble metal Pt and much larger than TIs, Weyl TSMs, and 4d/5d transition metals. Our work not only suggests a kind of TSM family with interesting Dirac CNL around Fermi level, but also paves the way for searching large intrinsic SHC materials in complex CNL TSM systems.

Calibrating DFT Formation Enthalpy Calculations by Multifidelity Machine Learning

“…In addition to the already synthesized materials, those unrealized hypothetical materials provide potential opportunities for energy and environmental materials, − structural materials, and electronic devices, , and as shown in Table and Figure b, many of these materials that are estimated stable by E hull ML might have underestimated stability in the MP database.…”

Two-Dimensional Van Der Waals Materials for Spin-Orbit Torque Applications

“…Such a discrepancy between the SOT conductivity and the critical switching current density have also been reported by , and the physics at work might depend on the saturation magnetization, the Dzyaloshinskii-Moriya interaction, and the magnetic damping, which require future efforts to understand. Recently, another topological semimetal, Ta 3 As, was predicted to has a large SOT conductivity around 150 × 10 3 (ħ/2e) (Ωm) -1 (Hou et al, 2021). This prediction promotes further research on SOT devices based on 2D semimetals with topological and superconductivity properties.…”

Electronic band crossing in sliding bilayer graphene: Tight-binding calculations and symmetry group representation analysis

“…Recently, the topic of band crossings has been extensively revisited in the context of topological characterization of the electronic structure of semimetals. [5][6][7][8][9][10] It is well established that if nonsymmorphic symmetries are present in a crystalline lattice, they will enforce the crossing of electronic bands. [11][12][13][14] Dirac and/or Weyl points are formed and they are globally stable.…”

“…[11][12][13][14] Dirac and/or Weyl points are formed and they are globally stable. [5][6][7][8][9][10] The band crossing can also occur at generic k points in the Brillouin zone and is independent of the symmetry properties of the system, including the lattice symmetries and the reality of the Hamiltonian. This case is called accidental band crossings that were first discussed by Herring in 1937.…”