We discuss devices for detection of the topological insulator phase based on the two-path electron interference. For that purpose we consider buckled silicene for which a local energy gap can be opened by vertical electric field to close one of the paths and for which the quantum spin Hall insulator conditions are controlled by the Fermi energy. In quantum spin Hall phase the interference is absent due to the separation of the spin currents and the conductance of the devices include sharp features related to localized resonances. In the normal transport conditions the two-path interference produces a regular Aharonov-Bohm oscillations in the external magnetic field.Quantum spin Hall (QSH) insulators [1-3] form a class of two-dimensional topological insulators with bulk energy gap and topologically protected currents of a fixed spin-orbital helicity. The QSH phase [4] is discussed for bulk nanostructures including HgTe quantum wells [5][6][7][8] and InAs/GaSb interfaces [9,10] as well as graphenelike monolayer Xenes materials [11,12], including silicene [13][14][15][16][17]. The QSH conditions in silicene occur for the Fermi energy near the charge neutrality point [13][14][15][16][17]. The Fermi energy in 2D monolayer materials can be controlled by external gating. In the QSH phase the spin currents are confined by opposite edges of the sample, which was used for proposals of spin sources and spin filters in silicene [18][19][20][21][22][23]. In this paper we propose electron interferometer devices that can be used for detection of the QSH transport conditions. The devices are based on the idea of two-path interference and the spin separation by the split silicene ribbon [18]. We consider a double slit interference device as well as a quantum ring and find that in the normal phase one observes smooth Aharonov-Bohm conductance oscillations while in the QSH regime only sharp conductance features due to the localized resonances with circular current loops are observed. In silicene both the localized resonances and the Aharonov-Bohm oscillations can be intentionally switched off by applying a local electric field to one of the arms of the split channels, due to the buckling of the crystal lattice that translates the electric field into a local energy gap [24,25] that stops the current flow.The schematics of the double slit interferometer depicted in [Fig. 1(a)]. The electrons are fed from the left by the silicene ribbon of a zigzag edge of 6.5 nm width. The zigzag ribbon supports the spin-polarized edge transport at the Fermi energy E F ∈ (−3, 3) meV with respect to the charge neutrality point [see the dispersion relation in Fig. 1(b)]. In the quantum spin Hall insulator phase the opposite spin currents flow at the opposite edges of the ribbon [see Fig. 1(a)]. The input lead splits into two channels of the same width. In the topological phase this spindle-shaped connection separates the opposite spin currents to the two channels [ Fig. 1(a)]. The split channels are connected to semi-infinite open plane of silicene [ F...