Zobrazeno 1 - 10
of 62
pro vyhledávání: '"Zeyher, Roland"'
Publikováno v:
Phys. Rev. B 106, 224512 (2022)
The study of the charge excitations in cuprates is presently an interesting topic because of the development of new and precise x-ray experiments. Based on a large-$N$ formulation of the two-dimensional $t$-$J$ model, which allows us to consider all
Externí odkaz:
http://arxiv.org/abs/2212.08794
Autor:
Zeyher, Roland, Greco, Andres
Publikováno v:
Phys. Rev. B 98, 224504 (2018)
We study the static charge correlation function in an one-band model on a square lattice. The Hamiltonian consist of effective hoppings of the electrons between the lattice sites and the Heisenberg Hamiltonian. Approximating the irreducible charge co
Externí odkaz:
http://arxiv.org/abs/1812.03891
Autor:
Greco, Andrés, Zeyher, Roland
Publikováno v:
Supercond. Sci. Technol. 29, 015002 (2016)
Using the large-$N$ limit of the $t$-$J$ model and allowing also for phonons and the electron-phonon interaction we study the isotope effect $\alpha$ for coupling constants appropriate for YBCO. We find that $\alpha$ has a minimum at optimal doping a
Externí odkaz:
http://arxiv.org/abs/1511.05096
Autor:
Yamase, Hiroyuki, Zeyher, Roland
Publikováno v:
New J. Phys. 17, 073030 (2015)
We study an interacting electronic system exhibiting a spin nematic instability. Using a phenomenological form for the spin fluctuation spectrum near the spin-density-wave (SDW) phase, we compute the spin nematic susceptibility in energy and momentum
Externí odkaz:
http://arxiv.org/abs/1503.07646
Autor:
Zeyher, Roland
Publikováno v:
Phys. Rev. B 91, 054513 (2015)
We study bond-order parameters for generalized $t$-$J$ models on a square lattice. Using the plane-wave limit the considered order parameters form basis functions for irreducible representations of the symmetry transformations of the point group and
Externí odkaz:
http://arxiv.org/abs/1406.6846
Autor:
Yamase, Hiroyuki, Zeyher, Roland
Publikováno v:
Phys. Rev. B 88, 125120 (2013)
We compute Raman scattering intensities via the lowest-order coupling to the bosonic propagator associated with orbital nematic fluctuations in a minimal model for iron pnictides. The model consists of two bands on a square lattice exhibiting four Fe
Externí odkaz:
http://arxiv.org/abs/1306.4267
Autor:
Zeyher, Roland, Greco, Andrés
Publikováno v:
Phys. Rev. B87, 224511 (2013)
We present results for magnetic excitations in doped copper oxides using the random phase approximation and itinerant electrons. In the [1,0] direction the observed excitations resemble dispersive quasi-particles both in the normal and superconductin
Externí odkaz:
http://arxiv.org/abs/1303.5975
Autor:
Yamase, Hiroyuki, Zeyher, Roland
Publikováno v:
PRB 88, 180502(R) (2013)
Recent experiments suggest that besides of antiferromagnetic fluctuations nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation we study superconductivity from nematic fluctuations
Externí odkaz:
http://arxiv.org/abs/1303.3806
Autor:
Zeyher, Roland, Greco, Andrés
Publikováno v:
EPL, 93 (2011) 67002
The isotope coefficient $\beta$ of the magnetic penetration depth in the superconducting state is studied at T=0 for a $d$-CDW and a nodal metal model. Disregarding superconductivity the Fermi surface of the first model possesses arcs whereas the sec
Externí odkaz:
http://arxiv.org/abs/1102.3864
Autor:
Yamase, Hiroyuki, Zeyher, Roland
Publikováno v:
Phys. Rev. B 83, 115116 (2011)
Motivated by recent transport and neutron scattering experiments suggesting an orientational symmetry breaking in underdoped cuprates we present a theoretical study of Raman scattering near a d-wave Pomeranchuk instability (PI). The d-wave component
Externí odkaz:
http://arxiv.org/abs/1010.0296