Silicon spin chains at finite temperature: dynamics of Si(553)-Au

Abstract

When gold is deposited on Si(553), the surface self-assembles to form a periodic array of steps with nearly perfect structural order. In scanning tunneling microscopy these steps resemble quasi-one-dimensional atomic chains. At temperatures below ~50 K the chains develop tripled periodicity. We recently predicted, on the basis of density-functional theory calculations at T=0, that this tripled periodicity arises from the complete polarization of the electron spin on every third silicon atom along the step; in the ground state these linear chains of silicon spins are antiferromagnetically ordered. Here we explore, using ab-initio molecular dynamics and kinetic Monte Carlo simulations, the behavior of silicon spin chains on Si(553)-Au at finite temperature. Thermodynamic phase transitions at T>0 in one-dimensional systems are prohibited by the Mermin-Wagner theorem. Nevertheless we find that a surprisingly sharp onset occurs upon cooling---at about 30 K for perfect surfaces and at higher temperature for surfaces with defects---to a well-ordered phase with tripled periodicity, in good agreement with experiment.

9 pages, 9 figures

References in corpus (9)

• An integrated approach to the assessment of long range correlation in time series data
• Intrinsic magnetism at silicon surfaces
• Competing periodicities in fractionally filled one-dimensional bands
• Double Au rows on Si(553) surface
• Structural models for the Si(553)-Au atomic chain reconstruction
• Systematic investigation of the structure of the Si(553)-Au surface from first principles
• Spectroscopic evidence for spin-polarized edge states in graphitic Si nanowires
• Ab initio study of the double row model of the Si(553)-Au reconstruction
• Phase transition at finite temperature in one dimension: Adsorbate ordering in Ba/Si(111)3x2

Cited by in corpus (5)

• Evidence for Long-Range Spin Order Instead of a Peierls Transition in Si(553)-Au Chains
• Spin Chains and Electron Transfer at Stepped Silicon Surfaces
• Spontaneous Appearance of Low-dimensional Magnetic Electron System on Semiconductor Nanostructures
• Temperature dependent ARPES of the metallic-like bands in Si(553)-Au
• Adsorbate induced manipulation of 1D atomic nanowires: Soliton mediated degradation of long-range order in the Si(553)-Au system