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Pressure-induced reconstructive phase transition in Cd3 As2

DOI: 10.1103/PhysRevMaterials.5.024209 DOI Help

Authors: Monika Gamza (University of Central Lancashire) , Paolo Abrami (University of Bristol) , Lawrence V. D. Gammond (University of Bristol) , Jake Ayres (University of Bristol) , Israel Osmond (University of Bristol) , Takaki Muramatsu (University of Bristol) , Robert Armstrong (University of Bristol) , Hugh Perryman (University of Bristol) , Dominik Daisenberger (Diamond Light Source) , Sitikantha Das (University of Bristol; Indian Institute of Technology) , Sven Friedemann (University of Bristol)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review Materials , VOL 5

State: Published (Approved)
Published: February 2021
Diamond Proposal Number(s): 19319

Abstract: Cadmium arsenide ( Cd 3 As 2 ) hosts massless Dirac electrons in its ambient-condition tetragonal phase. We report x-ray diffraction and electrical resistivity measurements of Cd 3 As 2 upon cycling pressure beyond the critical pressure of the tetragonal phase and back to ambient conditions. We find that, at room temperature, the transition between the low- and high-pressure phases results in large microstrain and reduced crystallite size, both on rising and falling pressure. This leads to nonreversible electronic properties, including self-doping associated with defects and a reduction of the electron mobility by an order of magnitude due to increased scattering. This paper indicates that the structural transformation is sluggish and shows a sizable hysteresis of over 1 GPa. Therefore, we conclude that the transition is first-order reconstructive, with chemical bonds being broken and rearranged in the high-pressure phase. Using the diffraction measurements, we demonstrate that annealing at ∼ 200 ∘ C greatly improves the crystallinity of the high-pressure phase. We show that its Bragg peaks can be indexed as a primitive orthorhombic lattice with a HP ≈ 8.68 Å , b HP ≈ 17.15 Å , and c HP ≈ 18.58 Å . The diffraction study indicates that, during the structural transformation, a new phase with another primitive orthorhombic structure may also be stabilized by deviatoric stress, providing an additional venue for tuning the unconventional electronic states in Cd 3 As 2 .

Journal Keywords: Chemical bonding; Compressive strength; Crystal defects; Crystal structure; Electrical conductivity; First order phase transitions; Hall effect; Pressure effects; Structural phase transition; Topological materials; Topological phases of matter; Transport

Subject Areas: Materials, Physics


Instruments: I15-Extreme Conditions

Added On: 02/03/2021 10:18

Discipline Tags:

Materials Science Quantum Materials Physics Hard condensed matter - electronic properties

Technical Tags:

Diffraction X-ray Powder Diffraction