Regular Article

Thermodynamic and electrical properties of laser-shocked liquid deuterium

¹ Shanghai Institute of Laser Plasma, CAEP, P.O. Box 800-229, Shanghai 201800, P.R. China
² IFSA Collaborative Innovation Center, Shanghai Jiaotong University, Shanghai 200240, P.R. China

^a e-mail: hezy1213@foxmail.com

Received: 12 May 2017
Received in final form: 14 July 2017
Published online: 16 January 2018

Abstract

Liquid deuterium at high pressure and temperature has been observed to undergo significant electronic structural changes. Reflectivity and temperature measurements of liquid deuterium up to around 70 GPa were obtained using a quartz standard. The observed specific heat of liquid deuterium approaches the Dulong-Petit limit above 1 eV. Discussions on specific heat indicate a molecular dissociation below 1 eV and fully dissociated above 1.5 eV. Also, the electrical conductivity of deuterium estimated from reflectivity reaches ~1.3 × 10⁵ (Ω⋅m)^-1, proving that deuterium in this condition is a conducting degenerate liquid metal and undergo an insulator-metal transition. The results from specific heat, carrier density and conductivity agreed well with each other, which might be a reinforcement of the insulator-metal transition and the molecular dissociation. In addition, a new correction method of reflectivity in temperature calculation was proposed to improve the accuracy of temperature results. A new “dynamic calibration” was introduced in this work to make the experiments simpler and more accurate.