TITLE : Computational Modeling of Competing Quantum Magnetic Phases and Possible Quantum Spin Liquid Candidates
ABSTRACT :
After a brief introduction to fundamentals of quantum magnetism, I shall discuss on our studies on a ferrimagnetic lattice of alternating spin-1 and spin-1/2 chain with nearest neighbour (NN) and next-nearest neighbour (NNN) antiferromagnetic interactions along with the z-component of the Dzyaloshinskii-Moriya (DM) interactions. The linear spin-wave theory and density matrix renormalization group (DMRG) methods study reveal that these competing exchange and DM interactions introduce strong quantum fluctuations in every lattice site, which in effect destroys the ferrimagnetic order and due to which all the signatures of ferrimagnetism vanish completely [1]. I shall also discuss the possible quantum spin liquid phases in a dimer-based material, Yb2Te5O13 and in a hyperhoneycomb random lattices, NaYbW2O8 with two compositions, which were synthesized and thermodynamic and mu-SR studies were carried out by our experimental colleagues [2]. In fact, after finding the exchange constants, single ion anisotropy and biaxial anisotropy, our Monte Carlo based prediction of incommensurate phases at certain temperatures for all the spin lattice systems indicate these as the possible QSL candidates. In fact, since the neutron scattering data is missing, we have verified our results with the experimental mu-SR data. Many more detailed experimental and quantum theoretical studies are necessary to identify these as the elusive quantum spin liquid candidates [2]. Finally, I shall show the nonlinear magneto-electric effect in a toy model (finite size spin-orbital lattice) with tuning of the Hubbard and spin-orbit coupling interactions [3].
References:
1. A. Lahiri, S. K Pati, J. Phys.: Cond. Matt. 34, 175802 (2022); S. Satpathy, S. Sarkar, S. K Pati, Phys. Rev. B (accepted, 2026).
2. R. Kumar, A. G. Francis, et al. Phys. Rev. B 111, 094407 (2025); R. Kumar, A. G. Francis et. al, Phys. Rev. B (Letter) 111, L140411 (2025).
3. A. Lahiri, S. K Pati, Pramana 2022, 96, 155.
ABOUT THE SPEAKER :
Prof. Swapan K Pati is a prominent Indian quantum chemist and currently serves as a Professor in the Theoretical Sciences Unit (TSU), JNCASR (https://www.jncasr.ac.in/faculty/pati). He is also an Adjunct Professor of the New Chemistry Unit(NCU), Chemistry & Physics of Materials Unit (CPMU) and International Centre for Materials Science (ICMS) JNCASR. He is currently the Chairman of TSU, JNCASR. He works on photochemistry, thermoelectric materials, homogeneous and heterogeneous catalysis, energy storage and harvesting, and magnetic materials.
Professor Pati has received several of India’s highest scientific honors:
1) Shanti Swarup Bhatnagar Prize (2010) in Chemical Sciences.
2) J.C. Bose National Fellowship (Recipient in 2013, 2018, and 2024).
3) Fellowships: Elected Fellow of the Indian National Science Academy (INSA) (2018), Indian Academy of Sciences (IAS) (2009), and The World Academy of Sciences (TWAS) (2015).
4) Other Honors: Swarnajayanthi Fellowship (2007–12) and the BM Birla Science Prize (2008).
MEETING DETAILS :
Speaker: Prof. Swapan K Pati, Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru
Venue: A4 Conference Room, South Campus, IIT Mandi
Date and Time: June 8, 2026, Monday at 4:00 pm