Tunable Nodal Nets in Non-Symmorphic Compounds

Recently, a number of new semimetals with non-trivial energy bands crossings have been predicted. Such bands crossings are considered as new quasiparticles with no counterparts in high-energy physics and might lead to novel physical properties. Particular attention has been attracted by the nodal line semimetals; in some of them the exotic nodal net/chain patterns are found, formed from multiple nodal lines. In this work, we predict the emergence of stable nodal nets in non-symmorphic compounds under spin-orbit coupling, supported by two or more nodal lines protected by different symmetry-invariant transformations. Using first-principles density functional calculations, we present a few examples of real materials with multiple nodal lines. We show that strain and pressure can control the size and shape of the nodal lines, and even produce additional nodal lines. Such tunable nodal lines result in novel nodal nets with interesting characteristics, for example, a nodal net with a quantized size. Due to the tunable nature of the nodal nets, such non-symmorphic compounds can be a viable platform to explore potential new quasiparticles and their physical properties.