| Autor: |
Zhang, T. T., Miao, H., Wang, Q., Lin, J. Q., Cao, Y., Fabbris, G., Said, A. H., Liu, X., Lei, H. C., Fang, Z., Weng, H. M., Dean, M. P. M. |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
Phys. Rev. Lett. 123, 245302 (2019) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevLett.123.245302 |
| Popis: |
While condensed matter systems host both Fermionic and Bosonic quasi-particles, reliably predicting and empirically verifying topological states is only mature for Fermionic electronic structures, leaving topological Bosonic excitations sporadically explored. This is unfortunate, as Bosonic systems such a phonons offer the opportunity to assess spinless band structures where nodal lines can be realized without invoking special additional symetries to protect against spin-orbit coupling. Here we combine first-principles calculations and meV-resolution inelastic x-ray scattering to demonstrate the first realization of parity-time reversal ($\mathcal{PT}$) symmetry protected helical nodal lines in the phonon spectrum of MoB$_{2}$. This structure is unique to phononic systems as the spin-orbit coupling present in electronic systems tends to lift the degeneracy away from high-symmetry locations. Our study establishes a protocol to accurately identify topological Bosonic excitations, opening a new route to explore exotic topological states in crystalline materials. |
| Databáze: |
arXiv |
| Externí odkaz: |
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