Field-tunable magnetic order and excitations in quantum spin liquid candidate NaYbSe2

NaYbCh2 (Ch = O, S, Se) does not form magnetic order down to 50mK in the presence of considerably strong antiferromagnetic interactions, and is suggested to exhibit a highly fluctuating QSL ground state. By comparing the structure of our magnetic excitation spectra with the theoretical expectation from the spinon continuum, we conclude that the ground state of NaYbSe2 is a QSL with a spinon Fermi surface. Moreover, our recent results of NaYbSe2 reveal a dispersive magnetic excitation continuum with clear upper and lower excitation edges under magnetic fields (up to 4 T). To further complete the measurements at a higher magnetic field region (up to 9 T), determine the accurate magnetic interactions, and corroborate the spinon Fermi surface picture, we propose to measure momentum-dependent low energy magnetic excitations under magnetic fields.