Observation of Topological Nodal Fermion Semimetal Phase in ZrSiS (1604.00720v1)

Abstract: Unveiling new topological phases of matter is one of the current objectives in condensed matter physics. Recent experimental discoveries of Dirac and Weyl semimetals prompt to search for other exotic phases of matter. Here we present a systematic angle-resolved photoemission spectroscopy (ARPES) study of ZrSiS, a prime topological nodal semimetal candidate. Our wider Brillouin zone (BZ) mapping shows multiple Fermi surface pockets such as the diamond-shaped Fermi surface, ellipsoidal-shaped Fermi surface, and a small electron pocket encircling at the zone center (G) point, the M point and the X point of the BZ, respectively. We experimentally establish the spinless nodal fermion semimetal phase in ZrSiS, which is supported by our first-principles calculations. Our findings evidence that the ZrSiS-type of material family is a new platform to explore exotic states of quantum matter, while these materials are expected to provide an avenue for engineering two-dimensional topological insulator systems.

• The paper reveals a topological nodal fermion semimetal phase in ZrSiS by mapping distinct Fermi surfaces with synchrotron-based ARPES measurements.
• The study employs advanced ARPES and VASP-based band structure calculations to identify diamond-shaped, ellipsoidal, and electron pockets across key BZ points.
• The findings pave the way for exploring new quantum phenomena and 2D topological insulator systems within the extensive ZrSiS material family.

Observation of Topological Nodal Fermion Semimetal Phase in ZrSiS

This research paper presents a thorough analysis of the topological nodal fermion semimetal phase found in ZrSiS, utilizing state-of-the-art angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. The investigation focuses on unraveling the electronic properties and structural configurations that signify the presence of this phase, contributing substantially to the exploration of topological materials, particularly in the family of ZrSiS-type compounds.

Key Findings and Methodology

The paper employed synchrotron-based ARPES measurements, allowing the researchers to successfully identify and map multiple Fermi surface pockets within the Brillouin zone (BZ) of ZrSiS. The observed Fermi surfaces include diamond-shaped, ellipsoidal, and small electron pockets situated at the $\Gamma$, M, and X points respectively. These pockets indicate the spinless nature of the nodal fermion semimetal phase in ZrSiS, suggesting a new class of materials where novel quantum phenomena could be explored.

In computational aspects, the paper reports band structure calculations using the Vienna Ab-initio Simulation Package (VASP), applying generalized gradient approximation (GGA) for exchange-correlation functionals. The calculations corroborated the experimental findings, especially verifying the emergence of linearly dispersive surface states and the occurrence of Dirac line nodes in the bulk band structure.

Implications and Future Directions

The identification of a topological nodal semimetal phase in ZrSiS positions this material as a prime candidate for further exploration of unconventional quantum states. The research hints at the potential for developing two-dimensional topological insulator systems from the ZrSiS family, emphasizing the material's stability and non-toxic nature as significant advantages for practical applications. The broad family of ZrSiS-type materials, consisting of over 200 compounds, offers a virtually unexploited domain for discovering and engineering new topological phases.

Technical Advancements and Considerations

The paper's strong experimental framework offers a reliable methodology for researchers exploring the intricate electronic characteristics of topologically non-trivial systems. Conjoining ARPES measurements with sophisticated computational simulations provides a robust approach to validate theoretical predictions with empirical evidence. Future work might focus on applying similar methodologies to other candidate materials within the ZrSiS family, potentially unveiling a myriad of exotic states and enriching our understanding of topologically protected phenomena.

Conclusion

In conclusion, the documented observation of the nodal fermion semimetal phase in ZrSiS enriches the material's portfolio potentially useful for technological innovations in quantum computing and advanced electronics. The demonstrated methodologies and corroborated findings could inspire subsequent studies targeting the discovery of other topological materials and the practical realization of their distinctive properties. As the field of topological insulators and semimetals evolves, contributions such as this serve as critical reference points for both academic inquiry and industrial exploitation.