Publications (27)
Quantum fluctuations and strong mass renormalization in NiCl2-4SC(NH2)2
Y. Kohama, A. Sologubenko, N. R. Dilley +9
In a number of quantum paramagnets, magnetic field can induce a quantum phase transition to an antiferromagnetic state which exists for a range of fields Hc1 < H < Hc2. Generally,…
Exchange parameters of copper-based quasi-two-dimensional Heisenberg magnets measured using high magnetic fields and muon-spin rotation
P. A. Goddard, J. Singleton, P. Sengupta +9
Pulsed-field magnetization experiments (fields of up to 85 T and temperatures down to 0.4 K) are reported on nine organic Cu-based two-dimensional (2D) Heisenberg magnets.…
Interaction driven metal-insulator transition in strained graphene
Ho-Kin Tang, E. Laksono, J. N. B. Rodrigues +3
The question of whether electron-electron interactions can drive a metal to insulator transition in graphene under realistic experimental conditions is addressed. Using three repre…
Intrinsic Structural Disorder and the Magnetic Ground State in Bulk EuTiO3
A. P. Petrovic, Y. Kato, S. S. Sunku +8
The magnetic properties of single-crystal EuTiO3 are suggestive of nanoscale disorder below its cubic-tetragonal phase transition. We demonstrate that electric field cooling acts t…
Ordered magnetic phases of the frustrated spin-dimer compound Ba3Mn2O8
E. C. Samulon, Y. -J. Jo, P. Sengupta +4
Ba3Mn2O8 is a spin-dimer compound based on pairs of S=1, 3d^2, Mn^{5+} ions arranged on a triangular lattice. Antiferromagnetic intradimer exchange leads to a singlet ground state…
Spectral functions of the honeycomb lattice with both the Hubbard and long-range Coulomb Interactions
Ho-Kin Tang, Indra Yudhistira, Udvas Chattopadhyay +4
The absence of screening of the non-local Coulomb interaction in Dirac systems at charge neutrality leads to the breakdown of the Fermi liquid and divergence of the Fermi velocity.…
Efficient and realistic device modeling from atomic detail to the nanoscale
J. E. Fonseca, T. Kubis, M. Povolotskyi +8
As semiconductor devices scale to new dimensions, the materials and designs become more dependent on atomic details. NEMO5 is a nanoelectronics modeling package designed for compre…
Time of flight observables and the formation of Mott domains of fermions and bosons on optical lattices
M. Rigol, R. T. Scalettar, P. Sengupta +1
We study, using quantum Monte Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both c…
Skyrmion-driven topological Hall effect in a Shastry-Sutherland magnet
N. Swain, M. Shahzad, G. V. Paradezhenko +3
The Shastry-Sutherland model and its generalizations have been shown to capture emergent complex magnetic properties from geometric frustration in several quasi-two-dimensional qua…
Comparison of multiwavelength observations of 9 broad-band pulsars with the spectrum of the emission from an extended current with a superluminally rotating distribution pattern
H. Ardavan, A. Ardavan, J. Singleton +7
The observed spectra of 9 pulsars for which multiwavelength data are available from radio to - or -ray bands (Crab, Vela, Geminga, B0656+14, B1055-52, B1509-58, B1706-44, B1…
Response to Comment on "The role of electron-electron interactions in two-dimensional Dirac fermions"
Ho-Kin Tang, J. N. Leaw, J. N. B. Rodrigues +4
Hesselmann {\it et al}.~question one of our conclusions, namely, the suppression of Fermi velocity at the Gross-Neveu critical point for the specific case of vanishing long-range i…
Finite-temperature phase transition to plateau phase in a S=1/2 XXZ model on Shastry-Sutherland Lattices
T. Suzuki, P. Sengupta, Y. Tomita +1
We study the finite-temperature transition to the magnetization plateau in a model of interacting spins with longer range interactions and strong exchange anisotrop…
Ground state and thermal transitions in Field Induced spin-Supersolid Phase
P. Sengupta, C. D. Batista
We use a quantum Monte Carlo method to study the ground state and thermodynamic phase transitions of the spin supersolid phase in the S=1 Heisenberg model with uniaxial anisotropy.…
Asymmetric phase diagram and dimensional crossover in a system of spin-1/2 dimers under applied hydrostatic pressure
M. J. Coak, S. P. M. Curley, Z. Hawkhead +8
We present the magnetic and structural properties of [Cu(pyrazine)(glycine)]ClO under applied pressure. As previously reported, at ambient pressure this material consis…
Phase coherence, visibility, and the superfluid--Mott-insulator transition on one-dimensional optical lattices
P. Sengupta, M. Rigol, G. G. Batrouni +2
We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in…
Spin-hedgehog-derived electromagnetic effects in itinerant magnets
G. V. Paradezhenko, A. A. Pervishko, N. Swain +2
In itinerant magnets, the indirect exchange coupling of Ruderman-Kittel-Kasuya-Yosida type is known to stabilize incommensurate spin spiral. Whereas an account of higher order spin…
The role of electron-electron interactions in two-dimensional Dirac fermions
Ho-Kin Tang, J. N. Leaw, J. N. B. Rodrigues +4
The role of electron-electron interactions on two-dimensional Dirac fermions remains enigmatic. Using a combination of nonperturbative numerical and analytical techniques that inco…
Fractalization drives crystalline states in a frustrated spin system
Suchitra E. Sebastian, N. Harrison, P. Sengupta +7
We measure a sequence of quantum Hall-like plateaux at 1/q: 9 >= q >= 2 and p/q = 2/9 fractions in the magnetisation with increasing magnetic field in the geometrically frustrated…
Geometric Frustration and Dimensional Reduction at a Quantum Critical Point
C. D. Batista, J. Schmalian, N. Kawashima +5
We show that the spatial dimensionality of the quantum critical point associated with Bose--Einstein condensation at T=0 is reduced when the underlying lattice comprises a set of l…
Quantum Hall Bilayer as Pseudospin Magnet
O. Kyriienko, K. Wierschem, P. Sengupta +1
We revisit the physics of electron gas bilayers in the quantum Hall regime [Nature, 432 (2004) 691; Science, 305 (2004) 950], where transport and tunneling measurements provided ev…
Non-classicality of spin structures in condensed matter: An analysis of SrCuO
W. Y. Kon, T. Krisnanda, P. Sengupta +1
When two quantum systems are coupled via a mediator, their dynamics has traces of non-classical properties of the mediator. We show how this observation can be effectively utilised…
A stabilization mechanism for many-body localization in two dimensions
D. C. W. Foo, N. Swain, P. Sengupta +2
Experiments in cold atom systems see almost identical signatures of many body localization (MBL) in both one-dimensional () and two-dimensional () systems despite the the…
Using magnetostriction to measure the spin-spin correlation function and magnetoelastic coupling in the quantum magnet NiCl-4SC(NH)
V. S. Zapf, V. F. Correa, P. Sengupta +9
We report a method for determining the spatial dependence of the magnetic exchange coupling, , from magnetostriction measurements of a quantum magnet. The organic Ni …
Comment on ``Ground State Phase Diagram of a Half-Filled One-Dimensional Extended Hubbard Model''
A. W. Sandvik, P. Sengupta, D. K. Campbell
In Phys. Rev. Lett. 89, 236401 (2002), Jeckelmann argued that the recently discovered bond-order-wave (BOW) phase of the 1D extended Hubbard model does not have a finite extent in…
Field Induced Supersolid Phase in Spin-One Heisenberg Models
P. Sengupta, C. D. Batista
We use quantum Monte Carlo methods to demonstrate that the quantum phase diagram of the S=1 Heisenberg model with uniaxial anisotropy contains an extended supersolid phase. We also…
Topological Confinement and Superconductivity
K. A. Al-Hassanieh, C. D. Batista, P. Sengupta +1
We derive a Kondo Lattice model with a correlated conduction band from a two-band Hubbard Hamiltonian. This mapping allows us to describe the emergence of a robust pairing mechanis…
Isotope effect in quasi-two-dimensional metal-organic antiferromagnets
P. A. Goddard, J. Singleton, C. Maitland +9
Although the isotope effect in superconducting materials is well-documented, changes in the magnetic properties of antiferromagnets due to isotopic substitution are seldom discusse…