arXiv subjects

Junichi Okamoto

Publications and source records attributed to Junichi Okamoto.

21 records · Page 2Linked to original sources

arXiv2016

Distinct surface and bulk charge density waves in ultrathin 1T-TaS2

We employ low-frequency Raman spectroscopy to study the nearly commensurate (NC) to commensurate (C) charge density wave (CDW) transition in 1T-TaS2 ultrathin flakes protected from oxidation. We identify new modes originating from C phase CDW phonons that are distinct from those seen in bulk 1T-TaS2. We attribute these to CDW modes from the surface layers. By monitoring individual modes with temperature, we find that surfaces undergo a separate, low-hysteresis NC-C phase transition that is decoupled from the transition in the bulk layers. This indicates the activation of a secondary phase nucleation process in the limit of weak interlayer interaction, which can be understood from energy considerations.

cond-mat.mtrl-sci↗

arXiv2016

Editorial: Emergence in driven solid-state and cold-atom systems

We briefly summarize the current status of driven solid-state and cold-atom systems, and introduce articles compiled in the Focus Section in Zeitschrift für Naturforschung A, Volume 71, Issue 10 (2016)

cond-mat.quant-gas↗

arXiv2012

Spin-exchange-induced dimerization of an atomic 1-D system

Using low-temperature scanning tunneling microscopy, we demonstrate an unambiguous 1-D system that surprisingly undergoes a CDW instability on a metallic substrate. Our ability to directly and quantitatively measure the structural distortion of this system provides an accurate reference for comparison with first principles theory. In comparison to previously proposed physical mechanisms, we attribute this particular 1-D CDW instability to a ferromagnetic state. We show that though the linear arrayed dimers are not electronically isolated, they are magnetically independent, and hence can potentially serve as a binary spin-memory system.

cond-mat.str-el↗