Structure and electronic spectroscopy of steps on GaAs(110) surfaces

► Used scanning tunneling microscopy to study steps on GaAs(110) surface. ► Determined structure of As-edge steps on GaAs(110) surface. ► Determined spectrum of electronic states of As-edge steps on GaAs(110) surface. ► Found states of As-edge steps that extend into the GaAs band gap. ► Observed compensating defects (that minimize charge) at As-edge steps.