**Abstract:**

There is a lot of interest in finding and identifying novel

quantum materials. We here focus on d1 materials with a

strong spin-orbit coupling, which are supposed to realize a much

higher symmetry than SU(2), an emergent SU(4) symmetry [1,2].

In fact, α-ZrCl3 is expected to host the SU(4) Heisenberg model

on the honeycomb lattice with a large frustration [3]. These

SU(4) materials potentially realize a new type of spin liquids,

a gapped Z4 spin liquid [4]. We present new density matrix

renormalization group (DMRG) studies on the SU(4)

Heisenberg model on the honeycomb lattice to show that

the ground state is indeed gapped and symmetric

with respect to all the symmetries, indicating

the existence of a gapped spin liquid in this

system [5]. The topological entanglement entropy

is close to the expected value for the Z4 spin liquid,

which has 16 superselection sectors in the thermodynamic limit.

[1] M.G.Y., M. Oshikawa, and G. Jackeli, Phys. Rev. Lett. 121, 097201 (2018).

[2] M.G.Y., M. Oshikawa, and G. Jackeli, Phys. Rev. B 104, 224436 (2021).

[3] P. Corboz et al., Phys. Rev. X 2, 041013 (2012).

[4] M.G.Y., and S. Fujimoto, arXiv:2111.14470 (2021).

[5] M.G.Y., K. Penc, and F. Pollmann, to appear.