Quantum phases of spin-1 system on 5/7 and 3/4 skewed ladders

Abstract:
Spin ladders are quantum magnetic systems that have piqued the interest in the past few decades due to their unique characteristics, which are significantly dependent on the topology of the system. A large number of compounds with a ladder like structure have been discovered through experiment [1]. Depending on the bond topologies, the ladders are referred to as zigzag ladder, 3/4, 3/5, 5/5 and 5/7 skewed ladders [2]. In this talk, I will discuss about the quantum phase transitions of frustrated antiferromagnetic (AF) Heisenberg spin systems on the 5/7 and 3/4 skewed two leg ladder geometries [3, 4]. These systems can be formed by periodically removing rung bonds from the zigzag ladders. These ladders have a fixed isotropic AF exchange interaction (J2=1) between the nearest-neighbor spins along the legs and a varying isotropic AF exchange interaction (J1) along the rungs. As a function of J1, these systems show many interesting ground states (GS) which vary from different types of nonmagnetic to ferrimagnetic GS. The study of various GS properties such as spin gap, spin-spin correlations, spin density and bond order reveal that the 5/7 skewed ladder has many phases like antiferromagnetic, ferrimagnetic and re-entrant nonmagnetic phase. The 5/7 system also shows the presence of spin current at specific J1 values due to simultaneous breaking of both reflection and spin parity symmetries.

[1] Rafaela A.L. Silva and Manuel Almeida, J. Mater. Chem. C 9 (2021) 10573
[2] G. Giri, D. Dey, M. Kumar, S. Ramasesha and Z.G. Soos, Phys. Rev. B 95 (2017) 224408
[3] S. Das, D. Dey, M. Kumar and S. Ramasesha, Phys. Rev. B 104 (2021) 125138
[4] S. Das, D. Dey, S. Ramasesha and M. Kumar, J. Appl. Phys. 129 (2021) 223902