Ultrafast Dynamics in Normal and CDW States of 2H-NbSe<sub>2</sub>
ORAL
Abstract
We have performed femtosecond pump-probe reflectivity study of the carrier and lattice dynamics using near-IR pump and white broadband probe at temperatures below and above the charge density wave transition in single crystal NbSe2. The temperature dependence of the frequency of the coherent damped oscillations show a second order softening when approaching TCDW. This mode can be described as a combination of two acoustic phonons, one of which has Kohn anomaly in a broad range of temperatures. We extracted basic characteristics of the soft mode and its anharmonic decay. Global analysis fits from femtosecond to nanosecond scale were applied to describe the relaxation dynamics from the broadband transient reflectivity data.
*This work was supported by the National Science Foundation under Grant No. ECCS-1711015. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357.
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Presenters
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Goran Karapetrov
- Physics and Materials Science and Engineering, Drexel University
- Department of Physics & Department of Materials Science and Engineering, Drexel University
- Physics and Materials Science and Engineering, Drexel Univiversity