67 citations · 405 across the 17 of their papers we have counts for
17 papers
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…
Simulation of melting of two dimensional Lennard-Jones solids
Keola Wierschem, Efstratios Manousakis
We study the nature of melting of a two dimensional (2D) Lennard-Jones solid using large scale Monte Carlo simulation. We use systems of up to 102,400 particles to capture the deca…
Quantum simulation of 3He impurities and of 4He interstitials in solid 4He
Keola Wierschem, Efstratios Manousakis
We have studied the role of an atomic 3He impurity and an interstitial 4He atom in two- and three-dimensional solid 4He using path integral Monte Carlo (PIMC) simulation. We find t…