SI

Shams Sohel Islam

Paul Scherrer Institute, Indian Institute of Science Education and Research Thiruvananthapuram, Maharshi Dayanand University Rohtak, Guru Ghasidas University

ORCID iD 0000-0003-0101-5143
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About

My research focuses on the experimental investigation of quantum materials, particularly low-dimensional and frustrated magnets, spin-orbit-coupled systems, and unconventional superconductors. In these systems, the fundamental degrees of freedom—spin, charge, orbital, and lattice—are strongly intertwined, giving rise to emergent phases such as quantum spin liquids (QSL), charge-density waves, superconductivity etc. My experimental expertise centers on local spectroscopic probes, primarily μSR and NMR, complemented by bulk measurements such as magnetization, specific heat, and transport. I investigate these materials under extreme conditions, including ultra-low temperatures, high magnetic fields, hydrostatic pressure, and uniaxial strain, enabling microscopic insight into competing ground states.

A major part of my work explores how reduced dimensionality and frustration stabilize exotic quantum phases. In the one-dimensional bond-alternating spin-chain NaVOPO4, we observed a field-induced gapless Tomonaga–Luttinger liquid state above the energy scale of a Bose–Einstein-condensed phase, directly confirming the theoretically predicted repulsive interactions between spinless fermions [PRB (Lett.) 109, L060406 (2024)]. Extending these ideas to higher dimensions, my work on frustrated lattices has uncovered a variety of unconventional magnetic ground states. In the quasi-2D square-cupola SrTiOCu4(PO4)4, I demonstrated a commensurate antiferromagnetic state with gapped spin-wave excitations arising from the interplay of frustration and Dzyaloshinskii–Moriya anisotropy [PRB 97, 174432 (2018)]. In a mixed-spin pyrochlore lattice, I uncovered the coexistence of unconventional superparamagnetic behavior with long-range ferrimagnetic order [PRB 102, 134433 (2020)].

Another major research direction involves spin-orbit-entangled Mott insulators, where the interplay of electron correlations, spin–orbit coupling, crystal-field effects, stabilizes anisotropic exchange between Jeff=1/2 moments. Our studies on a triangular-lattice YbZn2GaO5 revealed persistent spin-liquid-like excitations and emphasized the role of structural disorder in shaping the ground state [PRB (submitted)]. In YbBO3, I demonstrated a broad fluctuating regime with slow spin dynamics stabilized by low-dimensionality, frustration, and non-magnetic site disorder [PRB 107, 064421 (2023)]. I also investigated a honeycomb-lattice BiYbGeO5, revealing disordered ground state driven by anisotropic exchange interactions [PRB 108, 134408 (2023)].

Beyond Mott insulators, I have worked extensively on correlated metallic systems such as cuprates, kagome metals, and transition-metal dichalcogenide superconductors, where superconductivity, charge order, time-reversal-symmetry-breaking often coexist or compete. A central focus of my postdoctoral research has been the controlled tuning of these phases using external parameters. In the Nb-doped kagome superconductor Cs(V0.93Nb0.07)3Sb5, we demonstrated a pressure-induced transition from chiral charge order to a time-reversal-symmetry-breaking superconducting state [Comm. Phys. 8, 318 (2025)]. In layered dichalcogenides such as (4H/2H)-Nb(Se/S)2, I showed that pressure significantly enhances the superfluid density while leaving the superconducting gap nearly unchanged, revealing unconventional scaling between superfluid density and Tc [PRR 7, 013324 (2025)]. Additionally, our uniaxial-strain study of La1.885Ba0.115CuO4 revealed a strongly anisotropic response: in-plane stress enhances three-dimensional superconductivity while suppressing spin-stripe order, whereas c-axis compression reduces Tc but leaves the magnetic state largely unchanged, highlighting the key role of lattice symmetry in governing competing phases [Comm. Phys. 8, 291 (2025)].

Overall, my work combines advanced local probes under extreme-conditions to uncover, tune, and control emergent phases in quantum materials, with the long-term goal of engineering quantum states relevant for next-generation technologies.

Employment

  • Paul Scherrer Institute Postdoctoral Researcher
    2023 - Present

Education

  • Indian Institute of Science Education and Research Thiruvananthapuram P.hD.
    2016 - Present
  • Maharshi Dayanand University Rohtak Bachelor of Education (B.Ed.)
    2014 - 2015
  • Guru Ghasidas University M.Sc.
    2012 - 2014
  • University of Calcutta B.Sc.
    2009 - 2012

Projects & Funding

Projects & funding information is unavailable.

Publications (17)