In neuromorphic computing, memristors (or “memory resistors”) have been primarily studied as key elements in artificial synapse implementations, where the memristor provides a variable weight with intrinsic long-term memory capabilities, based on its modifiable resistive-switching characteristics. Here, we demonstrate an efficient methodology for simulating resistive-switching of HfO2 memristors within Synopsys TCAD Sentaurus—a well established, versatile framework for electronic device simulation, visualization and modeling. Kinetic Monte Carlo is used to model the temporal dynamics of filament formation and rupture wherein additional band-to-trap electronic transitions are included to account for polaronic effects due to strong electron-lattice coupling in HfO2. The conductive filament is modeled as oxygen vacancies which behave as electron traps as opposed to ionized donors, consistent with recent experimental data showing p-type conductivity in HfOx films having high oxygen vacancy concentrations and ab-initio calculations showing the increased thermodynamic stability of neutral and charged oxygen vacancies under conditions of electron injection. Pulsed IV characteristics are obtained by inputting the dynamic state of the system—which consists of oxygen ions, unoccupied oxygen vacancies, and occupied oxygen vacancies at various positions—into Synopsis TCAD Sentaurus for quasi-static simulations. This allows direct visualization of filament electrostatics as well as the implementation of a nonlocal, trap-assisted-tunneling model to estimate current-voltage characteristics during switching. The model utilizes effective masses and work functions of the top and bottom electrodes as additional parameters influencing filament dynamics. Together, this approach can be used to provide valuable device- and circuit-level insight, such as forming voltage, resistance levels and success rates of programming operations, as we demonstrate.

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Purpose This paper aims to problematise critiques raised against customer accounting’s numeric focus, which risks controlling and simplifying customers rather than facilitating closer engagement. This analysis suggests ways to better account for what it is that customers buy, why they do so and how to better serve them. Design/methodology/approach Service-dominant logic (SDL) is a marketing ideology that recognises the active role of customers in value creation. Seven customer accounting techniques are appraised against SDL principles to identify strengths and shortfalls in logic and application. Findings Customer accounting techniques align with SDL’s beneficiary-oriented and relational view of customers. Weaker alignment is found regarding a focus on outputs rather than outcomes, silence about the customer’s role in co-creating value and failure to recognise contextual circumstances. Research limitations/implications The analysis uses prototypical descriptions of customer accounting techniques. Actual applications could offset weaknesses or raise other shortfalls. Practical implications For each area of SDL, the authors suggest avenues for integrating SDL into customer accounting using related literature and building on concepts within customer accounting techniques. Originality/value SDL contrasts with the traditional, goods-dominant logic that underscores much of accounting. SDL is used to critically and constructively evaluate customer accounting techniques.