Emergent bound states and impurity pairs in chemically doped Shastry-Sutherland system

Abstract

Impurities often play a defining role in the ground states of frustrated quantum magnets. Studies of their effects are crucial in understanding of the phase diagram in these materials. SrCu 2 (BO 3 ) 2 , an experimental realization of the Shastry-Sutherland (SS) lattice, provides a unique model system for such studies using both experimental and numerical approaches. Here we report effects of impurities on the crystals of bound states, and doping-induced emergent ground states in Mg-doped SrCu 2 (BO 3 ) 2 , which remain stable in high magnetic fields. Using four complementary magnetometry techniques and theoretical simulations, a rich impurity-induced phenomenology at high fields is discovered. The results demonstrate a rare example in which even a small doping concentration interacts strongly with both triplets and bound states of triplets, and thus plays a significant role in the magnetization process even at high magnetic fields. Our findings provide insights into the study of impurity effects in geometrically frustrated quantum magnets.

Thermodynamic, Dynamic, and Transport Properties of Quantum Spin Liquid in Herbertsmithite from an Experimental and Theoretical Point of View

“…The scaling in (T χ ′′ ) is clearly seen in both this function and variable E. This confirms both the feasibility of Eq. (14) and the similarity of the HF metals and frustrated magnets properties. The scaled data acquired in measurements on such structurally different strongly correlated systems as ZnCu 3 (OH) 6 Cl 2 , Ce 0.925 La 0.075 Ru 2 Si 2 , (D 3 O)Fe 3 (SO 4 ) 2 (OD) 6 , and YbRh 2 Si 2 merge in a single curve over almost three decades in the scaled variables, thus confirming that these strongly correlated Fermi-systems exhibit universal scaling behavior and symptomatic of the existence of a new state of matter [17,58].…”

“…We note that the impurities randomly located at nanoscale level can support QSL as it is observed in measurements on Zn x Cu 4−x OH 6 Cl 2 with 1 ≥ x ≥ 0.8, while at x > 0.8 glassy dynamics emerges [5]. Moreover, the impurities randomly located at nanoscale level can stabilize QSL as it is observed in measurements on the verdazyl-based complex Zn(hfac) 2 (A x B 1−x ) [15], and make QSL stable in high magnetic fields, as it takes place in case Mg-doped SrCu 2 (BO 3 ) 2 [14].…”

Phase diagram of the Shastry-Sutherland Compound SrCu2(BO3)2 under extreme combined conditions of field and pressure

“…The TDO technique has been previously proven to be a valuable tool [11,40,41] for probing both the behavior of pure SrCu 2 (BO 3 ) 2 in the spin-dimer phase and the ambient-pressure behavior of doped SrCu 2−x Mg x (BO 3 ) 2 . It allows measurement of the change in magnetization at sub-Kelvin temperatures, high pressures, and high magnetic fields (see Appendix A 2for details).…”

Towards understanding the magnetic properties of the breathing pyrochlore compound Ba3Yb2Zn5O11: A single crystal study

“…The theoretical values of µ 0 H c1 and µ 0 H c2 are indicated by vertical dash lines. As alluded to earlier, the TDO frequency f is an extremely sensitive measurement of the magnetic susceptibility [48,55,56] and reveals fine details of changes in the magnetic response of sample. We show in Fig.…”

“…The LC circuit, powered by a tunnel diode operating in its negative resistance region, was tuned to resonance in a frequency range between 10 and 50 MHz. The shift in the resonance frequency f , which is related to the change in the sample magnetization M (df /dH ∝ d 2 M/dH 2 ) [48], was then recorded. The TDO method measures the resonance frequency to a very high precision [47] which enables identifying changes in the magnetic moments down to ∼ 10 −12 emu compared to ∼ 10 −8 emu in SQUID magnetometry measurements.…”