Condensed Matter/Materials & Biological Physics Seminar with Andriy Nevidomskyy on Quantum Melting of Spin 'Solids' in 2D

For several decades, the attention of both theoretical and experimental physicists has focused on finding examples of quantum spin liquids — exotic phases of matter characterized by the spin fractionalization, whereby the energy and momentum are carried not by spin waves, but by emergent elementary excitations. By contrast, defining a quantum spin ‘solid’ as a state that spontaneously breaks the lattice translation symmetry, I shall pose the following question — how do quantum solids ‘melt’ and how does entanglement establish itself in a quantum spin liquid ? To answer this question, I shall present our recent work on several 2D systems, from the familiar spin-1/2 on frustrated lattices [1], to the perhaps less familiar models of spin-1 [2] and SU(3) objects [3]. We study these models using the density matrix renormalization group (DMRG) and infinite projected entangled-pair states (iPEPS) techniques, supplemented by the analytical mean-field and linear flavor wave theory calculations. I shall also discuss another mechanism of quantum ‘melting’, induced by a strong magnetic field — the conventional picture is that this process can be understood as a Bose-Einstein condensation of the auxiliary bosons. Here we show [1] that a more exotic, non-BEC transition occurs when magnetic frustration drives the system across the Lifshitz point, and we find an exotic bosonic liquid that avoids the BEC altogether — so-called Bose metal with algebraic correlations.

[1] S. Sur, Y. Xu S.-S. Gong, and A.H. Nevidomskyy, Multi-criticality and field induced non-BEC transition in frustrated magnets, Phys. Rev. Lett. 132, 066701 (2024).

[2] Y. Xu, T. Fu, J. Hasik, and A.H. Nevidomskyy, Quantum Melting of Spin-1 Dimer Solid Induced by Inter-chain Couplings, arXiv:2209.09986. 

[3] Y. Xu, S. Capponi, J.-Y. Chen, L. Vanderstraeten, J. Hasik, A. H. Nevidomskyy, M. Mambrini, K. Penc and D. Poilblanc, Phase diagram of the chiral SU(3) antiferromagnet on the kagome lattice, Phys. Rev. B. 108, 195153 (2023).