Reversible displacive transformation in MnTe polymorphic semiconductor

Abstract

Displacive transformation is a diffusionless transition through shearing and shuffling of atoms. Diffusionless displacive transition with modifications in physical properties can help manufacture fast semiconducting devices for applications such as data storage and switching. MnTe is known as a polymorphic compound. Here we show that a MnTe semiconductor film exhibits a reversible displacive transformation based on an atomic-plane shuffling mechanism, which results in large electrical and optical contrasts. We found that MnTe polycrystalline films show reversible resistive switching via fast Joule heating and enable nonvolatile memory with lower energy and faster operation compared with conventional phase-change materials showing diffusional amorphous-to-crystalline transition. We also found that the optical reflectance of MnTe films can be reversibly changed by laser heating. The present findings offer new insights into developing low power consumption and fast-operation electronic and photonic phase-change devices.

Polymorphism of CdTe in the Few‐Monolayer Limit

“…In fact, utilizing the polymorphism for non-volatile memory application was reported recently for another telluride, MnTe. [24] Furthermore, the inverted structure may become a building block of currently unknown 2D vdW-bonded CdTe. The investigation of this issue is currently underway.…”

Chemical Vapor Deposition-Grown Nonlayered α-MnTe Nanosheet for Photodetectors with Ultrahigh Responsivity and External Quantum Efficiency

“…As a nonlayered p-type semiconductor with a multiphase, α-MnTe has an ordered antiparallel magnetic moment with a Néel temperature of 307 K. It has been explored in memristor, magnetism, , thermoelectric, and photocatalytic applications and has shown superior properties like an above room temperature Néel temperature, good stability, high thermal conductivity, high carrier concentration, and reversible phase change. Since the controllable preparation of the 2D α-MnTe crystal is hard to achieve, most research has remained on the thin film until now, while the growth of the high quality crystal is limited to molecular beam epitaxy which is hard to industrialize.…”

Nanometer-Thick Metastable Zinc Blende γ-MnTe Single-Crystalline Films for High-Performance Ultraviolet and Broadband Photodetectors

“…MnTe is a typical polymorphism and stabilizes in hexagonal NiAs-type α-phase [nickeline (NC), Figure S1a] under normal atmospheric conditions, showing a phase change from α-phase to β-phase [wurtzite, Figure S1b], and then to γ-phase [zinc-blende, Figure S1c], and finally to δ-phase [salt-rock, Figure S1d] with the increase of temperature in the phase diagram. − All of these MnTe phases exhibit antiferromagnetic (AFM) ground states. − Recently, anisotropic magnetoresistance memory and magnetic anisotropy of α-MnTe have been reported to show the availability in AFM spintronic and memristive devices. , Thanks to the polymorphism, reversible resistive switching correlated to the reversible displacive transformation, which is between the α-phase (nickeline) and the β-phase (wurtzite), is found in MnTe and demonstrates a stronger competition in nonvolatile memory than in conventional phase-change Ge–Sb–Te materials . Interestingly, Balan et al reported the magnetic ordering transfer from the antiferromagnetic state to the paramagnetic one and the bandgap broadening from 1.3 to 2.1 eV when α-MnTe is confined to 2D form .…”