Pressure Dependence of the EFG in Semimetallic Arsenic and Antimony

Abstract

Abstract The pressure variation of the axial EFG at the ion sites in semimetallic arsenic and antimony, at am-bient temperature, has been investigated using pulsed NQR. A weakly nonlinear decrease of the EFG is observed in both systems. The data are analyzed in terms of the lattice contribution to the EFG, which involves a lattice of point monopoles immersed in a uniform, compensating, background charge. The pressure dependence of the EFG obtained from the present measurements is far weaker than the pres-sure dependence of the calculated lattice contribution. Our results support previous suggestions that va-lence effects are important in determining the EFG in these semimetals.