Persistence of magnons in a site-diluted dimerized frustrated antiferromagnet

Abstract

We present inelastic neutron scattering and thermodynamic measurements characterizing the magnetic excitations in a disordered non-magnetic substituted spin-liquid antiferromagnet. The parent compound Ba 3 Mn 2 O 8 is a dimerized, quasi-two-dimensional geometrically frustrated quantum disordered antiferromagnet. We substitute this compound with non-magnetic vanadium for the S = 1 manganese atoms, Ba 3 (Mn 1-x V x ) 2 O 8 , and find that the singlet-triplet excitations which dominate the spectrum of the parent compound persist for the full range of substitution examined, x = 0.02 to 0.3. We also observe additional low-energy magnetic fluctuations which are enhanced at the greatest substitution values. These excitations may be a precursor to a lowtemperature random singlet phase which may exist in Ba 3 (Mn 1-x V x ) 2 O 8 .

Bose and Mott glass phases in dimerized quantum antiferromagnets

“…Such phases have also been seen in other materials [26][27][28][29] and in quantum Monte Carlo simulations [30][31][32][33][34].…”

“…Recent experiments on disordered quantum antiferromagnets have seen evidence for novel glassy phases, particularly in bromine-doped dichloro-tetrakis-thioureanickel (DTN) [25] where both Bose and Mott glass phases of bosonic quasiparticles have been observed. Such phases have also been seen in other materials [26][27][28][29] and in quantum Monte Carlo simulations [30][31][32][33][34].…”

Heat capacity of the site-diluted spin dimer system Ba3(Mn1−xVxSamulon1, Shapiro2, Fisher3 2011Phys. Rev. B113110View full textAdd to dashboardCite

“…N A is Avogadro's number, β = 1/k B T and α is the number of dimers per mole (where 1 mole refers to the formula unit Ba 3 (Mn 1−x V x ) 2 O 8 , such that α = 1 for x = 0). Recent INS studies found a negligible concentration dependence of both the spin gap ∆ and the triplet bandwidth for x < 0.05 22 . Therefore values of J 0 = 16.42 K, J 1 + J 4 + 2 (J 2 + J 3 ) = 5.31 K and g = 2.07 determined from the fit of the undiluted Ba 3 Mn 2 O 8 measurement (solid black circles) were held fixed for the fits of susceptibility data for the other samples.…”

Dynamic Structure Factor of Disordered Quantum Spin Ladders

“…While many studies have investigated the static and thermodynamic properties of such systems in the presence of disorder [8][9][10][11][12][13][14][15][16], the fate of quasi-particles under disorder is only rarely studied. Experimentally, however, increasingly improving resolution in spectroscopy like inelastic neutron or light scattering as well as intentional doping to control disorder in quantum materials [17][18][19][20][21][22][23], demands theoretical predictions for dynamical correlation functions of correlated quantum matter in the presence of disorder. Disordered QSL -The Hamiltonian of the disordered QSL for a fixed disorder configuration {J} is given byJ ν,n S ν,n · S ν+1,n ,(1) where the sum runs over all rungs and n = 1, 2 denotes arXiv:1806.01717v1 [cond-mat.str-el]…”