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arXiv · 2008.08732

Discovery of Light-induced Metastable Martensitic Anomaly Controlled by Single-Cycle Terahertz Pulses

X. Yang·B. Song·C. Vaswani·L. Luo·C. Sundahl·M. Mootz·J-H. Kang·Y. Yao·K-M Ho·I. E. Perakis·C. B. Eom·J. Wang
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Abstract

We report on an ultrafast photoinduced phase transition with a strikingly long-lived Martensitic anomaly driven by above-threshold single-cycle terahertz (THz) pulses in Nb$_3$Sn. A non-thermal, THz-induced depletion of low frequency conductivity indicates increased gap splitting of high energy $\Gamma_{12}$ bands by removal of their degeneracies which enhances the Martensitic phase. In contrast, optical pumping leads to a $\Gamma_{12}$ gap melting. Such light-induced non-equilibrium Martensitic instability persists up to a critical temperature $\sim$100 K, i.e., more than twice the equilibrium temperature, and can be stabilized beyond technologically-relevant, nanosecond timescales. Together with first-principle simulations, we identify a compelling THz tuning of structural fluctuations via E$_u$ phonons to achieve a non-equilibrium ordering at high temperatures far exceeding those for equilibrium states.

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X. Yang, B. Song, C. Vaswani, L. Luo, C. Sundahl, M. Mootz, J-H. Kang, Y. Yao, K-M Ho, I. E. Perakis, C. B. Eom, J. Wang. 2020-08-20. Discovery of Light-induced Metastable Martensitic Anomaly Controlled by Single-Cycle Terahertz Pulses. https://arxiv.org/abs/2008.08732

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