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Researchers Identify New Low-Dimensional Topological Dirac Semimetal

Scientists from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) have identified a new low-dimensional topological Dirac semimetal—TaPtTe5.

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The breakthrough was achieved by a team of researchers led by Professor Shaolong He from NIMTE. The study results have been reported in the Physical Review B journal.

In the recent past, the exploration of quantum materials that exhibit diverse symmetry-protected topological states has gained considerable attention in the field of condensed matter physics.

This is because of the exclusive physical properties of these materials, like superconductivity, charge carrier mobility, negative magnetoresistance, unsaturated large magnetoresistance, quantum oscillations, and chiral anomalies. Moreover, topological materials exhibit the potential for use in next-generation quantum computing and spintronics.

Most of the topological materials discovered so far show two-dimensional (2D) or three-dimensional (3D) structural characteristics. Professor He’s team from NIMTE identified TaPtTe5—a quasi-one-dimensional (quasi-1D) topological Dirac semimetal.

The high-quality single crystals of the layered ternary telluride TaPtTe5 were produced by using the self-flux method. The layered structure is formed of interchanging TaTe3 and PtTe2 chains.

Anisotropic magnetoresistance and nonlinear Hall effect at low temperatures were demonstrated in TaPtTe5. The researchers used the analysis of the de Haas–van Alphen (dHvA) oscillations, which were identified by using the field applied along the normal-to-layer direction, as the basis and observed the typical signatures of Dirac fermions. This suggests that TaPdTe5 is a new topological material.

The presence of two light effective masses of charge carriers and the related nonzero Berry phases indicated the nontrivial band topology of TaPtTe5. This aspect was confirmed further by means of the first-principles calculations.

The research showed that TaPtTe5 is another member of the quasi-1D topological semimetal class, which includes TaNiTe5 and TaPdTe5, both of which were discovered by Professor He’s team.

Furthermore, TaPtTe5 exhibited weak Van der Waals interlayer interaction. This shows that it is a perfect base for further studies on and applications of low-dimensional topological materials.

This research might offer insights into the exploration of topological superconductivity in this family of materials through voltage gating, high pressure, or chemical substitution. This is because the ternary tellurides Ta3Pd3Te14 and Ta4Pd3Te16 with analogous structural characteristics exhibit superconductivity.

Journal Reference:

Jiao, W.-H., et al. (2021) Anisotropic transport and de Haas–van Alphen oscillations in quasi-one-dimensional TaPtTe5. Physical Review B.


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