scholarly journals Excitation and Relaxation Dynamics of the Photo-Perturbed Correlated Electron System 1T-TaS2

2018 ◽  
Vol 9 (1) ◽  
pp. 44 ◽  
Author(s):  
Isabella Avigo ◽  
Ping Zhou ◽  
Matthias Kalläne ◽  
Kai Rossnagel ◽  
Uwe Bovensiepen ◽  
...  

We investigate the perturbation and subsequent recovery of the correlated electronic ground state of the Mott insulator 1T-TaS 2 by means of femtosecond time-resolved photoemission spectroscopy in normal emission geometry. Upon an increase of near-infrared excitation strength, a considerable collapse of the occupied Hubbard band is observed, which reflects a quench of short-range correlations. It is furthermore found that these excitations are directly linked to the lifting of the periodic lattice distortion which provides the localization centers for the formation of the insulating Mott state. We discuss the observed dynamics in a localized real-space picture.

2016 ◽  
Vol 879 ◽  
pp. 2158-2163 ◽  
Author(s):  
Misato Yamagata ◽  
Yasuhide Inoue ◽  
Yasumasa Koyama

The highly-correlated electron system Sr1-xSmxMnO3 (SSMO) with the simple-perovskite structure has been found to exhibit fascinating electronic states accompanying antiferromagnetic and ferromagnetic orderings. It was, in particular, reported that the electronic state for 0.46 ≤ x ≤ 0.54 was characterized by the coexistence state consisting of the A-type antiferromagnetic and ferromagnetic states. However, the features of the coexistence state in this Sm-content range have not been understood yet. We have thus investigated the crystallographic features of prepared SSMO samples with 0.46 ≤ x ≤ 0.55, mainly by transmission electron microscopy. As a result, all prepared SSMO samples were first confirmed to have the orthorhombic-Pnma structure at 300 K. When the temperature was lowered from 300 K, in the case of x=0.47, the disordered-Pnma state was found to be transformed into an orbital-modulated (OM) state accompanying an incommensurate modulation. The notable feature of the OM state is that the state becomes unstable with increasing Sm contents at 100 K. In other words, the OM state was never changed into the CE-type state with the orbital and charge modulations. In addition, no orbital-ordered state for the A-type antiferromagnetic ordering was also found for 0.46 ≤ x ≤ 0.55.


2019 ◽  
Vol 100 (20) ◽  
Author(s):  
Yusuke Nomura ◽  
Motoaki Hirayama ◽  
Terumasa Tadano ◽  
Yoshihide Yoshimoto ◽  
Kazuma Nakamura ◽  
...  

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3965-3968
Author(s):  
ATSUSHI SUGITA ◽  
TAKASHI SAITO ◽  
TAKAYOSHI KOBAYASHI ◽  
MASAHIRO YAMASHITA

A quasi-one-dimensional halogen-bridged mixed-valence metal complex is studied by time-resolved pump and probe spectroscopy with sub-5 fs time resolution. Two kinds of oscillatory signals are observed, which are attributed to the wave packet motions both in an electronic ground state and in a self-trapped exciton (STE) state. The onset of the wave packet motion is found to be delayed by about 50 fs, comparing with the ideal wave packet in the electronic excited state. The delay reflects the thermalization process in a free exciton (FE) state and a lattice relaxation process from FE to STE states.


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