https://doi.org/10.1140/epjb/e2019-100303-5
Regular Article
Specific heat, entropy and magnetic properties of high Tc superconductivity within the planar t−t′−J−V model
1
Department of Physics, University of Kalyani,
Kalyani-741235, India
2
Department of Physics, Krishnagar Government College,
Krishnagar-741101, India
a e-mail: subha.31connect@gmail.com
Received:
9
June
2019
Received in final form:
27
October
2019
Published online: 11 December 2019
The finite temperature properties of the high Tc cuprates are investigated by an exact method at optimal doping using t−t′−J−V model. The role of next-nearest-neighbor (NNN) hopping interaction t′ and nearest-neighbor Coulomb repulsion V on the total energy, specific heat, entropy, magnetic properties, etc. in the superconducting, as well as normal phase, are considered. Specific heat curves show a single peak structure in the parameter range suitable for existence of superconducting phase. Two peak structure in the specific heat curve is observed at sufficiently large values of V∕t. An asymmetry in specific heat curves and peak positions is observed for the hole- and electron-doped cuprates. Existence of a metallic phase is detected for positive t′∕t for V∕t ≤ 4J. Entropy calculation shows the system goes to a more disordered state with negative t′∕t and V∕t. A non-Fermi liquid behavior is revealed at low temperatures for positive t′ and small values of V . An asymmetry in Neel temperature is observed for the hole- and electron-doped cuprates. An unsaturated ferromagnetic phase emerges with an increase of V∕t. Schematic magnetic phase diagrams are shown.
Key words: Solid State and Materials
© EDP Sciences / Società Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2019