Figure 1.

Structural characterization of fully dense single-crystalline SnSe. (A) Bridgman-grown SnSe crystals with the crystal direction along the (100) face. (B) Neutron rocking curve of single-crystalline SnSe (19 g) measured at room temperature. The fwhm is estimated to be 0.48(1)°, indicating the high crystallinity of our Bridgman-grown SnSe samples. (C) X-ray phi-scan profile of SnSe (111) reflection. (D) Crystal structure of Pnma-SnSe along the a direction. (E) STM topography of SnSe (100) surface obtained at a bias voltage of 1.6 V and 200 pA constant current at 5 K, inset: zigzag chains of Sn–Se atoms. (F) Tunneling spectrum dI/dV obtained at 4.8 K on (100) surface, where VBM and CBM are valence band maximum and the conduction band minimum, respectively. E_F and E_g are the Fermi energy and the energy band gap, respectively.