Fig. 1
From: Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2
Flexible layer-structured MoTe2. a Schematic models of a single layer of MoTe2 with either P (Plus, CCW rotation) or M (Minus, CW)-type Te octahedral deformations in the cross-section view. Mo, blue; Te of a P layer, orange; Te of a M layer, purple. The red lines indicate Mo–Mo zigzags along the a axis. Orange and purple arc arrows represent the directions of the Te octahedral deformations. b Schematic models of bilayer MoTe2 with P−M and P+M configurations, counting from the bottom P layer. Gliding of the bottom P layer results in + (positive)/– (negative) interlayer shifts, where the signs refer to the CCW/CW displacement of Te–Te bonding lines. A zero-interlayer shear (λ = 0) corresponds to a centrosymmetric orthorhombic reference structure T0. c Examples of 1T´ and Td units of a M layer. A 1T´ unit requires the same sign of interlayer shearing (++ or −−) while those of a Td unit are different. d Three layers can glide individually to give four configurations. (1) 1T´-I, +M+ P+ with b–c angle of ~93.5o and (2) 1T´-II, −M−P− with b–c angle of ~86.5o;56 (3) Td↑, +M−P+ and (4) Td↓, −M+P− with orthogonal unit cells. The polarization along the ±c axis (green arrows) denotes as Td↑ and Td↓. Note that lattice a and b of the 1T´ structure are switched to match the zigzag direction as in the Td phase (b > a). The symbol x marks the inversion center
