Quantum mechanics

Anisotropy

Magnetic field

Antiferromagnetism

Fermi gas

Skyrmion

Acoustics

Lattice (music)

Physics

RKKY interaction

Magnetic moment

Fermi energy

Condensed matter physics

Electron

Hall effect

Physical Review Letters

We consider a C$_6$ invariant lattice of magnetic moments coupled via a Kondo exchange $J$ with a 2D electron gas (2DEG). The effective Ruderman-Kittel-Kasuya-Yosida interaction between the moments stabilizes a magnetic skyrmion crystal in the presence of magnetic field and easy-axis anisotropy. An attractive aspect of this mechanism is that the magnitude of the magnetic ordering wave vectors, ${\mathbf Q}_{\nu}$ ($\nu=1,2,3$), is dictated by the Fermi wave number $k_F$: $|{\mathbf Q}_{\nu} |=2k_F$. Consequently, the topological contribution to the Hall conductivity of the 2DEG becomes of the order of the quantized value, $e^2/h$, when $J$ is comparable to the Fermi energy $\epsilon_F$.

Skyrmion Crystal from RKKY Interaction Mediated by 2D Electron Gas