Volume 116, Number 3, November 2016
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||19 December 2016|
Phase diagram of the Kondo-Heisenberg model on honeycomb lattice with geometrical frustration
1 College of Science, Guilin University of Technology - Guilin 541004, China
2 LCP, Institute of Applied Physics and Computational Mathematics - Beijing 100088, China
3 Software Center for High Performance Numerical Simulation, China Academy of Engineering Physics Beijing 100088, China
Received: 19 July 2016
Accepted: 24 November 2016
We calculated the phase diagram of the Kondo-Heisenberg model on a two-dimensional honeycomb lattice with both nearest-neighbor and next-nearest-neighbor antiferromagnetic spin exchanges, to investigate the interplay between RKKY and Kondo interactions in the presence of magnetic frustration. Within a mean-field decoupling technology in slave-fermion representation, we derived the zero-temperature phase diagram as a function of Kondo coupling Jk and frustration strength Q. The geometrical frustration can destroy the magnetic order, driving the original antiferromagnetic (AF) phase to non-magnetic valence bond solids (VBS). In addition, we found two distinct VBS. As Jk is increased, a phase transition from AF to Kondo paramagnetic (KP) phase occurs, without the intermediate phase coexisting AF order with Kondo screening found in square lattice systems. In the KP phase, the enhancement of frustration weakens the Kondo screening effect, resulting in a phase transition from KP to VBS. We also found a process to recover the AF order from VBS by increasing Jk in a wide range of frustration strength. Our work may provide predictions for future experimental observation of new processes of quantum phase transitions in frustrated heavy-fermion compounds.
PACS: 75.30.Mb – Valence fluctuation, Kondo lattice, and heavy-fermion phenomena / 75.10.Jm – Quantized spin models, including quantum spin frustration / 73.43.Nq – Quantum phase transitions
© EPLA, 2016
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