Quantum phase is a fundamental physical quantity that characterizes the intrinsic properties of wave functions and quantum states, encoding critical information regarding the geometry, topology, and many-body correlations of a system. Traditionally, accessing this phase information has relied heavily on momentum-space probes or macroscopic transport measurements, making the direct visualization and quantification of quantum phases in real space a long-standing experimental challenge. In recent years, scanning tunneling microscopy/spectroscopy (STM/STS) have emerged as powerful platforms for directly probing quantum phases at the atomic scale, owing to their exceptional spatial resolution and sensitivity to local electronic states. This review summarizes the latest research progress of breakthroughs in STM-based quantum phase research, with a specific focus on four highly innovative methodologies and their corresponding experimental results.
We first discuss the probing of geometric phases via local Aharonov-Bohm (AB) interferometry, where nanoscale real-space interferometers constructed with STM enable direct resolution of coherent local density of states (LDOS) oscillations driven by external magnetic fluxes, allowing quantitative extraction of geometric phases. Next, we examine the resolution of topological phases through defect-induced backscattering; by carefully analyzing quasiparticle interference and associated wavefront dislocations around atomic defects, this approach enables direct extraction of topological invariants, such as winding numbers, and Berry phases without the need for an external magnetic field. We then describe the reconstruction of complex phase structures via order-parameter decomposition, highlighting advanced spatial decomposition techniques applied to strongly correlated and highly symmetric systems, such as magic-angle twisted bilayer graphene, which successfully disentangle intertwined orders and provide crucial experimental criteria for identifying microscopic ground states. Furthermore, we review the investigation of phase textures and topological defects using 2D lock-in techniques; applied to unconventional superconductors, these spatial filtering methods enable high-precision mapping of phase modulations in pair density wave (PDW) and charge density wave (CDW), and successfully visualize topological defects such as phase jumps, vortices, and half-dislocations. These transformative advances demonstrate that STM and associated analytical techniques effectively translate abstract mathematical quantum phases into visualizable, quantifiable real-space observables. This not only offers profound new experimental perspectives for decoding topological states of matter, symmetry breaking, and complex electronic correlations, but also lays a solid foundation for future phase engineering and the development of next-generation quantum devices.