Spin dynamics ofNiCl2−4SC(NH2)

Thermal Transport and Strong Mass Renormalization inNiCl2−4SC(NH2)2

“…For instance, in the dimer-based systems [4], the disorder in the leading intra-dimer coupling translates into the local modulation of the chemical potential which is equivalent to our Eq. (13). Thus, our Eq.…”

“…A modest decrease of H c1 by 1T should lead to an increase in κ 2 /κ 1 by a factor of 2. The leading impurity scattering (13) and, consequently, the resulting expression for the ratio κ 2 /κ 1 in (15) will remain valid for the other BEC magnets even though they may not be dominated by the single-ion anisotropy term. For instance, in the dimer-based systems [4], the disorder in the leading intra-dimer coupling translates into the local modulation of the chemical potential which is equivalent to our Eq.…”

“…Since the dressed bosonic excitations are related to the bare ones through Eq. (5), this transforms impurity scattering (13) into…”

“…In a remarkable contrast to these properties, peaks in the low-temperature thermal conductivity, κ, near H c1 and H c2 do not show any substantial asymmetry. We provide an explanation to this dichotomy by demonstrating that the leading boson-impurity scattering amplitude is also renormalized by quantum fluctuations, effectively canceling mass renormalization effect in κ.DTN is a quantum magnet with tetragonal crystal symmetry that exhibits a field-induced BEC [7,8,[12][13][14]] to a very good approximation [15]. The dominant single-ion uniaxial anisotropy D = 8.9 K splits the Ni S = 1 triplet into an S z = 0 ground state and an S z = ±1 excited doublet.…”

“…DTN is a quantum magnet with tetragonal crystal symmetry that exhibits a field-induced BEC [7,8,[12][13][14] to a very good approximation [15]. The dominant single-ion uniaxial anisotropy D = 8.9 K splits the Ni S = 1 triplet into an S z = 0 ground state and an S z = ±1 excited doublet.…”