Crystal structure of InBi under pressure up to 75 GPa

Abstract

InBi is studied by energy-dispersive diffraction with synchrotron radiation in a diamond-anvil cell under pressure up to 75 GPa. Three phase transitions are observed from its initial tetragonal structure tP4 with c/aϷ0.95 to another tP4 structure with c/aϷ0.65 typical for the ␤-Np structure, than to a disordered tetragonal body-centered structure tI2, and finally some hints are obtained for a transition to a cubic body-centered structure cI2. All these transformations are reversible with large hysteresis. InBi(tI2), phase III, shows initially a steep increase in c/a from 0.91 to 0.94, in the pressure range from 20 to 30 GPa, and a nearly constant value of about 0.96 above 55 GPa. Hints for the possible stability of a new phase IV are noticed in the present experiments on decompression from 75 GPa as admixture of new lines to phase III giving strong indications for a first-order phase transition with large hysteresis. The origin of the tetragonal distortion and the transformation to a cubic phase are discussed from the point of view of nesting the Fermi sphere in the Brillouin zone. ͓S0163-1829͑98͒00110-6͔ PHYSICAL REVIEW B

Structure solution in binary systems under high pressure: phase decomposition and phase synthesis

“…InBi was studied by energy-dispersive diffraction with synchrotron radiation in a diamond-anvil cell under pressure up to 75 GPa (Degtyareva et al, 1998). The initial tetragonal structure, tP4, space group P4/nmm, with c/a = 0.95, first transforms with a strong compression along the c axis to a similar tetragonal structure with c/a = 0.65 and then, at a higher pressure, to a tetragonal body-centered structure, bct, of a random (site-disordered) type.…”

Phase Transformations in Binary Alloys under High Pressure

“…The axi al ra ti o decreases wi th a decrease i n al l oy electro n concentra ti on. The possibl e expl anati on of thi s correl ati on shoul d b e accounted for by Bri l l oui n-zone{ Fermi-sphere Ùtti ng s di scussed i n pap ers [3,4].…”

“…Howev er, a tetra gonal di sto rti o n occurs i n Sn under pressure before the tra nsiti on to bcc, wi th the axi al ra ti o rea ching c= a = 0 : 9 6 (0 .68 i n the fct setti ng ) [20]. Si mil ar tetra gona l di storti on of b cc ha s b een observed under pressure i n the i soel ectro ni c comp ound InBi , wi th the sam e axi al rati o [3]. The dashed l i ne i n Fi g. 7 extendi ng fro m thi s p oint at n = 4 towards l ower el ectro n concentra ti on represents tetra gonal di sto rti ons f or b ct i n the Sn-ri ch al l oys wi th In and Hg under pressure [4,5,7].…”

“…Al l three com p ounds exi st at certa i n sto i chiom etri c com p ositi ons and ha ve crysta l structures of site-ordered typ e. The InBi com p ound was studi ed by energy-di spersive di˜ra cti on wi th synchro tro n ra di ati on i n a di am ond-an vil cell under pressure up to 75 G Pa [3]. Ini ti al tetra gona l structure is tP 4 , space gro up P 4 = nmm , wi th c= a = 0 : 9 5 .…”

Demonstration of InAsBi photoresponse beyond 3.5 μm

“…In our simulations, the lattice constant and strain are the main unknown parameters. The empirical lattice constant of tetragonal InBi has been determined; 18,19 however, Zinc Blend-InBi (ZB-InBi) has not been synthesized. There are uncertainties in the theoretically predicted lattice constant of ZB-InBi, with values ranging from 6.5 to 7.02 Å reported in the literature.…”