67 citations · 405 across the 17 of their papers we have counts for
15 papers · 1 filter
Magnons in a two dimensional transverse field XXZ model
Satyaki Kar, Keola Wierschem, Pinaki Sengupta
The XXZ model on a square lattice in the presence of a transverse magnetic field is studied within the spin wave theory to investigate the resulting canted antiferromagnet. The sma…
Detection of symmetry-protected topological order in AKLT states by exact evaluation of the strange correlator
Keola Wierschem, K. S. D. Beach
The strange correlator [Phys. Rev. Lett. 112, 247202 (2014)] has been proposed as a measure of symmetry protected topological order in one- and two-dimensional systems. It takes th…
Origin of modulated phases and magnetic hysteresis in TmB_4
Keola Wierschem, Sai Swaroop Sunku, Tai Kong +4
We investigate the low temperature magnetic phases in TmB_4, a metallic quantum magnet on the geometrically frustrated Shastry-Sutherland lattice, using co-ordinated experimental a…
Characterizing the Haldane phase in quasi-one-dimensional spin-1 Heisenberg antiferromagnets
Keola Wierschem, Pinaki Sengupta
We review the basic properties of the Haldane phase in spin-1 Heisenberg antiferromagnetic chains, including its persistence in quasi-one-dimensional geometries. Using large-scale…
Magnetism in a family of square lattice antiferromagnets Ni(pyz) ( Cl, Br, I, NCS; pyz = pyrazine)
J. Liu, P. A. Goddard, J. Singleton +23
The crystal structures of Ni(pyz) ( = Cl (\textbf{1}), Br (\textbf{2}), I (\textbf{3}) and NCS (\textbf{4})) were determined at 298~K by synchrotron X-ray powder diffra…
Strange correlations in spin-1 Heisenberg antiferromagnets
Keola Wierschem, Pinaki Sengupta
We study the behavior of the recently proposed "strange correlator" [Phys. Rev. Lett. {\bf 112}, 247202 (2014)] in spin-1 Heisenberg antiferromagnetic chains with uniaxial single-i…
Magnetic phases in the S=1 Shastry-Sutherland model with uniaxial anisotropy
Lei Su, Keola Wierschem, Pinaki Sengupta
We explore the field induced magnetic phases of an model with single-ion anisotropy and large Ising-like anisotropy on a Shastry Sutherland lattice over a wide range of…
Quenching the Haldane gap in spin-1 Heisenberg antiferromagnets
Keola Wierschem, Pinaki Sengupta
We consider a quasi-one-dimensional system of spin-1 Heisenberg antiferromagnetic chains in 2D and 3D hypercubic lattices with interchain coupling and uniaxial single-ion aniso…
Neel to spin-Peierls transition in a quasi-1D Heisenberg model coupled to bond phonons
Jason Cornelius Pillay, Keola Wierschem, Pinaki Sengupta
The zero and finite temperature spin-Peierls transitions in a quasi-one-dimensional spin-1/2 Heisenberg model coupled to adiabatic bond phonons is investigated using the Stochastic…
Magnetization plateaus in generalized Shastry-Sutherland models
Keola Wierschem, Pinaki Sengupta
We study an anisotropic Heisenberg antiferromagnet with ferromagnetic transverse spin exchange using exact quantum Monte Carlo methods. Such a model is relevant to a class of rare…
Dimensional Crossover in Quasi-one-dimensional Spin-1 Heisenberg Antiferromagnets
Keola Wierschem, Pinaki Sengupta
We study the quenching of the Haldane gap in quasi-one-dimensional systems of weakly coupled spin-1 antiferromagnetic Heisenberg chains. The critical interchain coupling Jc require…
Phase Diagram and Magnetic Excitations of Anisotropic Spin-One Magnets
Zhifeng Zhang, Keola Wierschem, Ian Yap +3
We use a generalized spin wave approach and large scale quantum Monte Carlo (QMC) simulations to study the quantum phase diagram and quasiparticle excitations of the S=1 Heisenberg…
Columnar antiferromagnetic order and spin supersolid phase on the extended Shastry-Sutherland lattice
Keola Wierschem, Pinaki Sengupta
We use large scale quantum Monte Carlo simulations to study an extended version of the canonical Shastry-Sutherland model -- including additional interactions and exchange anisotro…
Magnetic and nematic orderings in spin-1 antiferromagnets with single-ion anisotropy
Keola Wierschem, Yasuyuki Kato, Yusuke Nishida +2
We study a spin-one Heisenberg model with exchange interaction, J, uniaxial single-ion exchange anisotropy, D, and Zeeman coupling to a magnetic field, B, parallel to the symmetry…
Dimensional crossover in spin-1 Heisenberg antiferromagnets: a quantum Monte Carlo study
Keola Wierschem, Pinaki Sengupta
We present results of large scale simulations of the spin-1 Heisenberg antiferromagnet on a tetragonal lattice. The stochastic series expansion quantum Monte Carlo method is used t…