Untitled

Vojta, Thomas; Epperlein, Frank

doi:10.1002/(sici)1521-3889(199811)7:5/6<493::aid-andp493>3.3.co;2-h

Cited by 8 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is an extension compared to the ansatz of ref. 23 where all paths with the same length n had been given the same weight. The additional degrees of freedom improve the ground-state wavefunction for non-zero hole momentum taking into account that the quasiparticle state is not exactly s-like, see also Sec.…”

Section: Ground State Wavefunctionmentioning

confidence: 99%

“…However, for a description of magnetic properties or the spin response of the system these ground-state spin fluctuations would be essential, see e.g. 23 .…”

Section: Ground State Wavefunctionmentioning

confidence: 99%

“…For details see ref. 23 . The total ground-state energy depends on the initial momenta of the hole quasiparticles k m in (15).…”

Section: Ground State Wavefunctionmentioning

confidence: 99%

See 2 more Smart Citations

Charge correlations in the weakly doped model calculated by projection technique

Vojta

Becker

1998

Eur. Phys. J. B

View full text Add to dashboard Cite

We study frequency-and wave-vector dependent charge correlations in weakly doped antiferromagnets using Mori-Zwanzig projection technique. The system is described by the two-dimensional t-J model. The ground state is expressed within a cumulant formalism which has been successfully applied to study magnetic properties of the weakly doped system. Within this approach the ground state contains independent spin-bag quasiparticles (magnetic polarons). We present results for the charge-density response function and for the optical conductivity at zero temperature for different values of t/J. They agree well with numerical results calculated by exact diagonalization techniques. The density response function for intermediate and large momenta shows a broad continuum on energy scales of order of several t whereas the optical conductivity for ω > 0 is dominated by low energy excitations (at 1.5-2J). We show that these weak-doping properties can be well understood by transitions between excited states of spin-bag quasiparticles.

show abstract

Section: Ground State Wavefunctionmentioning

confidence: 99%

“…However, for a description of magnetic properties or the spin response of the system these ground-state spin fluctuations would be essential, see e.g. 23 .…”

Section: Ground State Wavefunctionmentioning

confidence: 99%

See 1 more Smart Citation

Charge correlations in the weakly doped model calculated by projection technique

Vojta

Becker

1998

Eur. Phys. J. B

View full text Add to dashboard Cite

show abstract

“…In this case not only accurate values for the ground-state energy but also for the sublattice magnetization result. 18,16 Following the outlined procedure, Eqs. ͑17͒ and ͑18͒ lead to…”

Section: ͑18͒mentioning

confidence: 99%

“…For the ground-state energy E g already a very good value results from this simple approach. 11,18 As was mentioned before for the staggered magnetization, one would have to extend the ansatz for ⍀ by allowing the parameter to depend on the distance R i ϪR j ,…”

Section: ͑18͒mentioning

confidence: 99%

Analytical approach to the Heisenberg antiferromagnet with nearest- and next-nearest-neighbor exchange

Köhler

Becker

1997

Phys. Rev. B

View full text Add to dashboard Cite

We investigate the ground-state energy of a two-dimensional Heisenberg antiferromagnet with competing nearest-and next-nearest-neighbor exchange interactions J 1 and J 2 . On the basis of a recently introduced cumulant technique we describe the transition from the usual antiferromagnetic phase to a so-called layered antiferromagnetic phase as a function of the ratio J 2 /J 1 . Whereas in the former phase the spins are approximately aligned antiparallel along the up and down sublattice, in the layered phase each of the two sublattices forms an antiferromagnetic lattice by itself. The result for the ground-state energy and for respective order parameters agree well with findings obtained from numerical methods. ͓S0163-1829͑97͒00937-5͔FIG. 1. Néel state for J 1 ӷJ 2 ͑left͒ and layered Néel state for J 2 ӷJ 1 ͑right͒.

show abstract

From Localization to Delocalization in the Quantum Coulomb Glass

Vojta¹,

Epperlein

Kilina

et al. 2000

phys. stat. sol. (b)

View full text Add to dashboard Cite

We numerically investigate how electron–electron interactions influence the transport properties of disordered electrons in two dimensions. Our study is based on the quantum Coulomb glass model appropriately generalized to include the spin degrees of freedom. In order to obtain the low‐energy properties of this model we employ the Hartree‐Fock based diagonalization, an efficient numerical method similar to the configuration interaction approach in quantum chemistry. We calculate the dc conductance by means of the Kubo‐Greenwood formula and pay particular attention to the spin degrees of freedom. In agreement with earlier results we find that electron–electron interactions can cause delocalization. For spinful electrons this delocalization is significantly larger than for spinless electrons.

show abstract

Untitled

Cited by 8 publications

References 0 publications

Charge correlations in the weakly doped model calculated by projection technique

Charge correlations in the weakly doped model calculated by projection technique

Analytical approach to the Heisenberg antiferromagnet with nearest- and next-nearest-neighbor exchange

From Localization to Delocalization in the Quantum Coulomb Glass

Contact Info

Product

Resources

About