AUTHOR=Zhang Li , Fang Fang , Cheng Lixin , Lin Huiming , Wang Kai 

TITLE=Obvious Surface States Connecting to the Projected Triple Points in NaCl’s Phonon Dispersion

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.789522

DOI=10.3389/fchem.2021.789522

ISSN=2296-2646

ABSTRACT=<p>With the development of computer technology and theoretical chemistry, the speed and accuracy of first-principles calculations have significantly improved. Using first-principles calculations to predict new topological materials is a hot research topic in theoretical and computational chemistry. In this work, we focus on a well-known material, sodium chloride (NaCl), and propose that the triple point (TP), quadratic contact triple point (QCTP), linear and quadratic nodal lines can be found in the phonon dispersion of NaCl with Fm<inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover accent="true"><mml:mn>3</mml:mn><mml:mo>¯</mml:mo></mml:mover></mml:mrow></mml:math></inline-formula> m type structure. More importantly, we propose that the clear surface states connected to the projected TP and QCTP are visible on the (001) surface. It is hoped that further experimental investigation and verification for these properties as mentioned above.</p>