Fingerprints of quantum spin ice in Raman scattering

Abstract

We develop a theory of the dynamical response of a minimal model of quantum spin ice (QSI) by means of inelastic light scattering. In particular, we are interested in the Raman response of the fractionalized U(1) spin liquid realized in the XXZ QSI. We show that the low-energy Raman intensity is dominated by spinon and gauge fluctuations. We find that the Raman response in the QSI state of that model appears only in the $T_{2g}$ polarization channel. We show that the Raman intensity profile displays a broad continuum from the spinons and coupled spinon and gauge fluctuations, and a low-energy peak arising entirely from gauge fluctuations. Both features originate from the exotic interaction between photon and the fractionalized excitations of QSI. Our theoretical results suggest that inelastic Raman scattering can in principle serve as a promising experimental probe of the nature of a U(1) spin liquid in QSI.Comment: 16 pages, 4 figure

Properties and application of SO(3) Majorana representation of spin: Equivalence with Jordan-Wigner transformation and exact Z2 gauge theories for spin models

“…But there is another N 2 constaints which take the form as (17). At first sight, the conditions (16) and (17) seem to be overcomplete.…”

“…Therefore, the mapping (15) or (16) and (17) give a correspondence between the SO(3) Majorana representation and the 1d Jordan-Wigner transformation. The SO(3) Majorana representation (Eq.…”

“…Throughout our discussion, we make no reference to the specific form of the spin Hamiltonian of the spin chain, thus the correspondence is between the two spin representations and can be applied to any one-dimensional spin Hamiltonian. On the other hand, the constraints in (16) and (17) take different form from the constrains that are previously discussed 8,31 , in which we pair up sites and demand that for each pair ij , γ i γ j = −i. In general there are multiple ways to fix the extra degrees of freedom in the SO(3) Majorana representation.…”

“…Actually the local Hilbert space of the four Majorana fermions in the Kitaev and the SO(4) chiral Majorana representation is the same as the one of the Abrikosov fermion representation 8 . Besides, special representations have been defined and applied to lattice spin models with exotic geometry, such as the quantum spin ice model [14][15][16] .…”

Raman spectroscopy evidence for dimerization and Mott collapse in α−RuCl3 under pressures

“…Raman spectrum simultaneously detects the lattice and magnetic excitations, and their mutual couplings [43,44]. It is an exemplary experimental tool to study competition between spin-orbit couplings [45][46][47][48], magnetism [43,44,49,50], and chemical bondings in Kitaev compounds [47,[51][52][53][54].…”