A Spectroscopic Study of the Insulator–Metal Transition in Liquid Hydrogen and Deuterium. Issue 2 (27th November 2019)

• Record Type: Journal Article
• Authors: Jiang, Shuqing; Holtgrewe, Nicholas; Geballe, Zachary M.; Lobanov, Sergey S.; Mahmood, Mohammad F.; McWilliams, R. Stewart; Goncharov, Alexander F.
• Is Part Of: Advanced science. Volume 7:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-27
• Subjects: extreme pressure and temperature -- hydrogen -- insulator‐to‐metal transition; Science -- Periodicals; 505
• DOI: 10.1002/advs.201901668
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: The insulator‐to‐metal transition in dense fluid hydrogen is an essential phenomenon in the study of gas giant planetary interiors and the physical and chemical behavior of highly compressed condensed matter. Using direct fast laser spectroscopy techniques to probe hydrogen and deuterium precompressed in a diamond anvil cell and laser heated on microsecond timescales, an onset of metal‐like reflectance is observed in the visible spectral range at P >150 GPa and T ≥ 3000 K. The reflectance increases rapidly with decreasing photon energy indicating free‐electron metallic behavior with a plasma edge in the visible spectral range at high temperatures. The reflectance spectra also suggest much longer electronic collision time (≥1 fs) than previously inferred, implying that metallic hydrogen at the conditions studied is not in the regime of saturated conductivity (Mott–Ioffe–Regel limit). The results confirm the existence of a semiconducting intermediate fluid hydrogen state en route to metallization. Abstract : By applying microsecond single‐ to several‐pulse laser heating in a diamond anvil cell in combination with pulsed broadband laser probing detected via a streak camera, the onset of metallic optical reflectance is determined in fluid hydrogen and deuterium above 3500 (1000) K at 150–172 GPa.