Abstract-Terahertz field control of in-plane orbital order in La0.5Sr1.5MnO4

• Timothy A Miller,
• Ravindra W Chhajlany,
• Luca Tagliacozzo,
• Bertram Green,
• Sergey Kovalev,
• Dharmalingam Prabhakaran,
• Maciej Lewenstein,
• Michael Gensch
• & Simon Wall

http://www.nature.com/ncomms/2015/150918/ncomms9175/full/ncomms9175.html

Nature Communications

 

6,

 

Article number:

 

8175

 

doi:10.1038/ncomms9175

Received

 

02 February 2015 

Accepted

 

27 July 2015 

Published

 

18 September 2015

In-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phases such as superconductivity; however, their origins are debated. Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition. Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field. Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation. Our results highlight the key role played by the Coulomb interaction in the control and manipulation of orbital order in the manganites and demonstrate a new way to use THz to understand and manipulate anisotropic phases in a potentially broad range of correlated materials.

Abstract-Anisotropic terahertz response of stretch-aligned composite films based on carbon nanotube-SiC hybrid structures

Ruili Wu,   Weilong Li,   Yun Wan,   Zhaoyu Ren,   Xin Long Xu and  Yixuan Zhou  

RSC Adv., 2015, Accepted Manuscript

DOI: 10.1039/C4RA14871A
Received 19 Nov 2014, Accepted 09 Mar 2015
First published online 10 Mar 2015
http://pubs.rsc.org/en/content/articlelanding/2015/ra/c4ra14871a#!divAbstract

Well-organized CNT-SiC hybrid structures were prepared by floating catalytic chemical vapor deposition (CCVD) process. The aligned CNTs-based composite materials were also fabricated by simply stretching. Gelatin and CNT-SiC hybrid structures were taken as the matrix and fillers, respectively. The alignment of CNT-SiC hybrids and anisotropic properties of the composite materials were discussed by the detection of THz time-domain spectroscopy technology. The results indicated that the anisotropic properties of CNT-SiC hybrids based composite films are better than the case of pure MWCNTs. The unique structure of hybrids not only largely favors the dispersion of CNTs in polymer matrix, but also favors the alignment of CNTs in the composites by stretching. The CNTs-based composite films with further improving the anisotropy are highly desirable for various modern applications in the electrical and optical industry (such as the polarizer).